Leonard Jason

Leonard A. Jason, PhD, is a professor of psychology at DePaul University in Chicago, Illinois, USA and Director of the Center for Community Research at DePaul University which includes the Depaul University Chronic Fatigue Syndrome Project.

Dr. Jason developed chronic fatigue syndrome after contracting infectious mononucleosis in 1989, necessitating a leave of absence from his university job for a year and a half. After recovering enough to return to work, he began studying chronic fatigue syndrome: “What I found was that the illness had a lousy name, chronic fatigue syndrome,” he recalled. “It had an even worse case definition. The tests used to assess people’s psychological conditions were inappropriate. The treatments being used were inappropriate. And the prevalence data was not very good. So I said to myself, ‘Boy, I’m gonna have business for the next 20 years.’” He has become one of the most respected and prolific researchers of chronic fatigue syndrome.

In 2008, David Tuller profiled for The New York Times Dr. Jason's experience as both living with and researching myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Education

 * 1975 - Ph.D., Clinical/Community Psychology, University of Rochester, Rochester, New York
 * 1971 - B.A., Psychology, Brandeis University, Waltham, Massachusetts

Awards

 * 2015, American Psychological Association’s award for Distinguished Professional Contributions to Applied Research
 * 2013, DePaul University College of Science and Health award for Excellence in Research
 * 2011, Rudy Perpich Senior Lectureship Award, presented to a distinguished CFS/FM scientist, physician or healthcare worker awarded by International Association for Chronic Fatigue Syndrome/Myalgic Encephalomyelitis
 * 2011, Tom Fellows award for outstanding contributions to the Oxford House organization
 * 1997, CSN ACTION Champion Award from the Chronic Fatigue Immune Dysfunction Syndrome Association of America (CAA)

Chronic Fatigue Syndrome Advisory Committee
Dr. Jason served as a voting member of the Chronic Fatigue Syndrome Advisory Committee for the U.S. Department of Health and Human Services from April 1, 2004 to April 1, 2011.

Open letter to The Lancet
Two open letters to the editor of The Lancet urged the editor to commission a fully independent review of the PACE trial, which the journal had published in 2011. The first, written in 2015, was sign by Dr. Jason and 5 of his colleagues. In 2016, thirty-six additional colleagues in the ME/CFS field, signed the second letter.
 * 13 November 2015, An open letter to Dr. Richard Horton and The Lancet
 * 10 February 2016, An open letter to The Lancet, again - Virology blog

Pediatric case definition
Dr. Jason is one of the authors of the Pediatric Case Definition for Myalgic Encephalomyelitis and Chronic Fatigue Syndrome:
 * 2006, "A Pediatric Case Definition for Myalgic Encephalomyelitis and Chronic Fatigue Syndrome""'Summary: For a diagnosis of chronic fatigue syndrome (CFS), most researchers use criteria that were developed by Fukuda et al. (1994), with modifications suggested by Reeves et al. (2003). However, this case definition was established for adults rather than children. A Canadian Case Definition (ME/CFS; Myalgic Encephalomyelitis/CFS) has recently been developed, with more specific inclusion criteria (Carruthers et al., 2003). Again, the primary aim of this case definition is to diagnose adult CFS. A significant problem in the literature is the lack of both a pediatric definition of ME/CFS and a reliable instrument to assess it. These deficiencies can lead to criterion variance problems resulting in studies labeling children with a wide variety of symptoms as having ME/CFS. Subsequently, comparisons between articles become more difficult, decreasing the possibility of conducting a meta-analysis. This article presents recommendations developed by the International Association of Chronic Fatigue Syndrome Pediatric Case Definition Working group for a ME/CFS pediatric case definition. It is hoped that this pediatric case definition will lead to more appropriate identification of children and adolescents with ME/CFS.'"

Studies

 * 2017, A content analysis of chronic fatigue syndrome and myalgic encephalomyelitis in the news from 1987 to 2013"Abstract - Objectives: The aim of this study was to analyze the content of American newspaper articles (n=214) from 1987 to 2013, in order to understand how the public digests information related to Chronic Fatigue syndrome, a controversial and misunderstood illness. Methods: A novel codebook derived from the scientific literature was applied to 214 newspaper articles collected from Lexis Nexis Academic®. These articles were coded quantitatively and frequency tables were created to delineate the variables as they appeared in the articles. Results: The etiology was portrayed as organic in 64.5% (n=138) of the articles, and there was no mention of case definitions or diagnostic criteria in 56.1% (n=120) of the articles. The most common comorbidity was depression, appearing in 22.9% (n=49) of the articles. In 55.6% (n=119) of the articles, there was no mention of prevalence rates. In 50.9% (n=109) of the articles, there was no mention of any form of treatment for the illness. A total of 19.4% (n=42) of the headlines mislabeled the name of the illness. Discussion: Based on descriptive statistics of all 214 coded articles, media communicated mixed messages for salient variables such as the name of the illness, its etiology and treatment."
 * 2017, Clinical criteria versus a possible research case definition in chronic fatigue syndrome/myalgic encephalomyelitis "Abstract - Background: The Institute of Medicine (IOM) recently developed clinical criteria for what had been known as chronic fatigue syndrome. Given the broad nature of the clinical IOM criteria, there is a need for a research definition that would select a more homogenous and impaired group of patients than the IOM clinical criteria. At the present time, it is unclear what will serve as the research definition. Purpose: The current study focused on a research definition which selected homebound individuals who met the four IOM criteria, excluding medical and psychiatric co-morbidities. Methods: Our research criteria were compared to those participants meeting the IOM criteria. Those not meeting either of these criteria sets were placed in a separate group defined by six or more months of fatigue. Data analyzed were from the DePaul Symptom Questionnaire and the 36-item Short-Form Health Survey (SF-36). Due to unequal sample sizes and variances, Welch’s F tests and Games-Howell post-hoc tests were conducted. Results: Using a large database of over 1000 patients from several countries, we found that those meeting a more restrictive research definition were even more impaired and more symptomatic than those meeting criteria for the other two groups. Conclusion: Deciding on a particular research case definition would allow researchers to select more comparable patient samples across settings, and this would represent one of the most significant methodologic advances for this field of study."
 * 2017, Article - "The PACE trial missteps on pacing and patient selection""Abstract - 'As others have pointed out a variety of complicating factors with the PACE trial (e.g. changing outcome criteria), I will limit my remarks to issues that involve the composition of adaptive pacing therapy and issues involving patient selection. My key points are that the PACE trial investigators were not successful in designing and implementing a valid pacing intervention and patient selection ambiguity further compromised the study’s outcomes.'"
 * 2017, A Prospective Study of Infectious Mononucleosis in College Students"'Abstract - Background: The present study aims to prospectively investigate possible biological and psychological factors present in college students who will go on to develop chronic fatigue syndrome (CFS) following Infectious Mononucleosis (IM). Identification of risk factors predisposing patients towards developing CFS may help to understand the underlying mechanisms and ultimately prevent its occurrence. Our study is enrolling healthy college students over the age of 18. Enrollment began in March of 2013 and is ongoing. Methods: Biological and psychological data are collected when students are well (Stage 1), when they develop IM (Stage 2), and approximately 6 months after IM diagnosis (Stage 3). Results: Two case studies demonstrate the progression of student symptomology across all three stages. Conclusion: The Case Studies presented illustrate the usefulness of a prospective research design that tracks healthy.'"
 * 2016, Comparing the DePaul Symptom Questionnaire with physician assessments: a preliminary study"'Results: The DSQ identified 60 and the physicians identified 56 as having a CCC diagnosis. The overall agreement between the two ratings on the diagnostic assessment part was moderate (Kappa = 0.45, p < .001). The sensitivity of DSQ was good (98%) while the specificity was 38%. Positive and negative predictive values were 92% and 75%, respectively. Conclusion: DSQ is useful for detecting and screening symptoms consistent with a CCC diagnosis in clinical practice and research. However, it is important for initial screening of self-report symptoms to be followed up by subsequent medical and psychiatric examination in order to identify possible exclusionary medical and psychiatric disorders.'"
 * 2016, Housebound versus nonhousebound patients with myalgic encephalomyelitis and chronic fatigue syndrome"'Abstract - Objectives: The objective of this study was to examine individuals with myalgic encephalomyelitis and chronic fatigue syndrome who are confined to their homes due to severe symptomatology. The existing literature fails to address differences between this group, and less severe, nonhousebound patient populations. Methods: Participants completed the DePaul Symptom Questionnaire, a measure of myalgic encephalomyelitis and chronic fatigue syndrome symptomology, and the SF-36, a measure of health impact on physical/mental functioning. ANOVAs and, where appropriate, MANCOVAS were used to compare housebound and nonhousebound patients with myalgic encephalomyelitis and chronic fatigue syndrome across areas of functioning, symptomatology, and illness onset characteristics. Results: Findings indicated that the housebound group represented one quarter of the sample, and were significantly more impaired with regards to physical functioning, bodily pain, vitality, social functioning, fatigue, post-exertional malaise, sleep, pain, neurocognitive, autonomic, neuroendocrine, and immune functioning compared to individuals who were not housebound. Discussion: Findings indicated that housebound patients have more impairment on functional and symptom outcomes compared to those who were not housebound. Understanding the differences between housebound and not housebound groups holds implications for physicians and researchers as they develop interventions intended for patients who are most severely affected by this chronic illness.'"
 * 2016, Estimating the disease burden of ME/CFS in the United States and its relation to research funding "'Abstract: At the National Institutes of Health (NIH), burden of disease is an important factor in funding decisions along with such factors as scientific opportunity, the quality of the science, and the interest of researchers. Recent studies have quantified the burden for a number of diseases in the United States and the NIH has used that information to analyze how its own funding patterns correspond to disease burden. However, the burden of disease has not been quantified for myalgic encephalomyelitis, also called chronic fatigue syndrome (ME/CFS) and is often underestimated due to a lack of research and the misperceptions about the nature of the disease...Even given the limitations arising from sparse data, this analysis demonstrates that federal research funding for this disease is far less than what would be expected by the burden of the disease. We conclude that the annual research funding for ME/CFS would need to increase twenty-five fold or more to be commensurate with disease burden. This level of funding would best leverage the growing interest of researchers and the significant scientific opportunities that exist to understand the pathology of this disease and to advance diagnostics and treatments.'"
 * 2016, Identifying Key Symptoms Differentiating Myalgic Encephalomyelitis and Chronic Fatigue Syndrome from Multiple Sclerosis"'Abstract:It is unclear what key symptoms differentiate Myalgic Encephalomyelitis (ME) and Chronic Fatigue syndrome (CFS) from Multiple Sclerosis (MS). The current study compared self-report symptom data of patients with ME or CFS with those with MS. The self-report data is from the DePaul Symptom Questionnaire, and participants were recruited to take the questionnaire online. Data were analyzed using a machine learning technique called decision trees. Five symptoms best differentiated the groups. The best discriminating symptoms were from the immune domain (i.e., flu-like symptoms and tender lymph nodes), and the trees correctly categorized MS from ME or CFS 81.2% of the time, with those with ME or CFS having more severe symptoms. Our findings support the use of machine learning to further explore the unique nature of these different chronic diseases.'"
 * 2016, Mortality in patients with myalgic encephalomyelitis and chronic fatigue syndrome
 * 2016, Deconstructing [[post-exertional malaise]: An exploratory factor analysis.] "'Abstract: Post-exertional malaise is a cardinal symptom of myalgic encephalomyelitis and chronic fatigue syndrome. There are two differing focuses when defining post-exertional malaise: a generalized, full-body fatigue and a muscle-specific fatigue. This study aimed to discern whether post-exertional malaise is a unified construct or whether it is composed of two smaller constructs, muscle fatigue and generalized fatigue. An exploratory factor analysis was conducted on several symptoms that assess post-exertional malaise. The results suggest that post-exertional malaise is composed of two empirically different experiences, one for generalized fatigue and one for muscle-specific fatigue.'"
 * 2016, Assessing current functioning as a measure of significant reduction in activity level "Abstract - Background: Myalgic encephalomyelitis and chronic fatigue syndrome have case definitions with varying criteria, but almost all criteria require an individual to have a substantial reduction in activity level. Unfortunately, a consensus has not been reached regarding what constitutes substantial reductions. One measure that has been used to measure substantial reduction is the Medical Outcomes Study Short-Form-36 Health Survey (SF-36). Purpose: The current study examined the relationship between the SF-36, a measure of current functioning, and a self-report measure of the percent reduction in hours spent on activities. Results: Findings indicated that select subscales of the SF-36 accurately measure significant reductions in functioning. Further, this measure significantly differentiates patients from controls. Conclusion: Determining what constitutes a significant reduction in activity is difficult because it is subjective to the individual. However, certain subscales of the SF-36 could provide a uniform way to accurately measure and define substantial reductions in functioning.
 * 2016, The Role of Infectious and Stress-related Onsets in Myalgic Encephalomyelitis and Chronic Fatigue Syndrome Symptomatology and Functioning
 * 2016, Educational Priorities for Healthcare Providers and Name Suggestions for Chronic Fatigue Syndrome: Including the Patient Voice
 * 2016, Intrinsic Functional Hypoconnectivity in Core Neurocognitive Networks Suggests Central Nervous System Pathology in Patients with Myalgic Encephalomyelitis: A Pilot Study (FULL TEXT) Abstract - Exact low resolution electromagnetic tomography (eLORETA) was recorded from nineteen EEG channels in nine patients with myalgic encephalomyelitis (ME) and 9 healthy controls to assess current source density and functional connectivity, a physiological measure of similarity between pairs of distributed regions of interest, between groups. Current source density and functional connectivity were measured using eLORETA software. We found significantly decreased eLORETA source analysis oscillations in the occipital, parietal, posterior cingulate, and posterior temporal lobes in Alpha and Alpha-2. For connectivity analysis, we assessed functional connectivity within Menon triple network model of neuropathology. We found support for all three networks of the triple network model, namely the central executive network (CEN), salience network (SN), and the default mode network (DMN) indicating hypo-connectivity in the Delta, Alpha, and Alpha-2 frequency bands in patients with ME compared to controls. In addition to the current source density resting state dysfunction in the occipital, parietal, posterior temporal and posterior cingulate, the disrupted connectivity of the CEN, SN, and DMN appears to be involved in cognitive impairment for patients with ME. This research suggests that disruptions in these regions and networks could be a neurobiological feature of the disorder, representing underlying neural dysfunction.
 * 2016 - qEEG / LORETA in Assessment of Neurocognitive Impairment in a Patient with Chronic Fatigue Syndrome: A Case Report (FULL TEXT) Abstract - Importance: Chronic Fatigue Syndrome (CFS) is a chronic disease resulting in considerable and widespread cognitive deficits. Accurate and accessible measurement of the extent and nature of these deficits can aid healthcare providers and researchers in the diagnosis of this condition, choosing interventions and tracking treatment effects. Here, we present a case of a middle-aged man diagnosed with CFS which began following a typical viral illness. Observations: LORETA source density measures of surface EEG connectivity at baseline were performed on 3 minutes of eyes closed deartifacted19-channel qEEG. The techniques used to analyze the data are described along with the hypothesized effects of the deregulation found in this data set. Nearly all (>90%) patients with CFS complain of cognitive deficits such as slow thinking, difficulty in reading comprehension, reduced learning and memory abilities and an overall feeling of being in a “fog.”Therefore, impairment may be seen in deregulated connections with other regions (functional connectivity); this functional impairment may serve as one cause of the cognitive decline in CFS. Here, the functional connectivity networks of this patient were sufficiently deregulated to cause the symptoms listed above. Conclusions and significance: This case report increased our understanding of CFS from the perspective of brain functional networks by offering some possible explanations for cognitive deficits in patients with CFS. There are only a few reports of using source density analysis or qEEG connectivity analysis for cognitive deficits in CFS. While no absolute threshold exists to advise the physician as to when to conduct such analyses, the basis of his or her decision whether or not to use these tools should be a function of clinical judgment and experience. These analyses may potentially aid in clinical diagnosis, symptom management, treatment response and can alert the physician as to when intervention may be warranted.
 * 2016 - Functional Neural Network Connectivity in Myalgic Encephalomyelitis (FULL TEXT)"Abstract - Myalgic Encephalomyelitis (ME) is a chronic illness with debilitating neurocognitive impairment that remains poorly understood. Previous studies have characterized cognitive deficits as a process by which brain abnormalities are inferred from pre-established testing paradigms using neuroimaging with low temporal resolution. Unfortunately, this approach has been shown to provide limited predictive power, rendering it inadequate for the study of neuronal communication between synchronized regions. More recent developments have highlighted the importance of modeling spatiotemporal dynamic interactions within and between large-scale and small-scale neural networks on a millisecond time scale. Here, we focus on recent emergent principles of complex cortical systems, suggesting how subtle disruptions of network properties could be related to significant disruptions in cognition and behavior found in ME. This review, therefore, discusses how electrical neuroimaging methods with time-dependent metrics (e.g., coherence, phase, cross-frequency coupling) can be a useful approach for the understanding of the cognitive symptoms in ME. By providing a platform for utilizing real-time alterations of the perpetual signals as an outcome, the disruptions to higher-level cognition typically seen in ME can be readily identified, creating new opportunities for better diagnosis and targeted treatments."
 * 2016, Case definitions integrating empiric and consensus perspectives
 * 2016, Comparing the DePaul Symptom Questionnaire with physician assessments: a preliminary study"'Results: The DSQ identified 60 and the physicians identified 56 as having a CCC diagnosis. The overall agreement between the two ratings on the diagnostic assessment part was moderate (Kappa = 0.45, p < .001). The sensitivity of DSQ was good (98%) while the specificity was 38%. Positive and negative predictive values were 92% and 75%, respectively. Conclusion: DSQ is useful for detecting and screening symptoms consistent with a CCC diagnosis in clinical practice and research. However, it is important for initial screening of self-report symptoms to be followed up by subsequent medical and psychiatric examination in order to identify possible exclusionary medical and psychiatric disorders.'"
 * 2016, Housebound versus nonhousebound patients with myalgic encephalomyelitis and chronic fatigue syndrome"'Abstract - Objectives: The objective of this study was to examine individuals with myalgic encephalomyelitis and chronic fatigue syndrome who are confined to their homes due to severe symptomatology. The existing literature fails to address differences between this group, and less severe, nonhousebound patient populations. Methods: Participants completed the DePaul Symptom Questionnaire, a measure of myalgic encephalomyelitis and chronic fatigue syndrome symptomology, and the SF-36, a measure of health impact on physical/mental functioning. ANOVAs and, where appropriate, MANCOVAS were used to compare housebound and nonhousebound patients with myalgic encephalomyelitis and chronic fatigue syndrome across areas of functioning, symptomatology, and illness onset characteristics. Results: Findings indicated that the housebound group represented one quarter of the sample, and were significantly more impaired with regards to physical functioning, bodily pain, vitality, social functioning, fatigue, post-exertional malaise, sleep, pain, neurocognitive, autonomic, neuroendocrine, and immune functioning compared to individuals who were not housebound. Discussion: Findings indicated that housebound patients have more impairment on functional and symptom outcomes compared to those who were not housebound. Understanding the differences between housebound and not housebound groups holds implications for physicians and researchers as they develop interventions intended for patients who are most severely affected by this chronic illness.'"
 * 2016, The Relationship between Age and Illness Duration in Chronic Fatigue Syndrome"'Abstract:Chronic fatigue syndrome (CFS) is a debilitating illness, but it is unclear if patient age and illness duration might affect symptoms and functioning of patients. In the current study, participants were categorized into four groups based upon age (under or over age 55) and illness duration (more or less than 10 years). The groups were compared on functioning and symptoms. Findings indicated that those who were older with a longer illness duration had significantly higher levels of mental health functioning than those who were younger with a shorter or longer illness duration and the older group with a shorter illness duration. The results suggest that older patients with an illness duration of over 10 years have significantly higher levels of mental health functioning than the three other groups. For symptoms, the younger/longer illness duration group had significantly worse immune and autonomic domains than the older/longer illness group. In addition, the younger patients with a longer illness duration displayed greater autonomic and immune symptoms in comparison to the older group with a longer illness duration. These findings suggest that both age and illness duration need to be considered when trying to understand the influence of these factors on patients."
 * 2016, Are Myalgic Encephalomyelitis and chronic fatigue syndrome different illnesses? A preliminary analysis (FULL TEXT) "Abstract - Considerable discussion has transpired regarding whether chronic fatigue syndrome is a distinct illness from Myalgic Encephalomyelitis. A prior study contrasted the Myalgic Encephalomyelitis International Consensus Criteria (ME-ICC; Carruthers et al., 2011) with the Fukuda et al. (1994) CFS criteria and found that the ME-ICC identified a subset of patients with greater functional impairment and physical, mental, and cognitive problems than the larger group who met Fukuda et al. (1994) criteria (Brown et al., 2013). The current study analyzed two discrete data sets and found that the ME-ICC identified more impaired individuals with more severe symptomatology."


 * /Studies for 2014 & 2015


 * /Studies for 2012 & 2013


 * /Studies for 2010 & 2011


 * /Studies for 2008 & 2009


 * /Studies for 2006 & 2007


 * /Studies for 2004 & 2005


 * /Studies for 2000 - 2003


 * /Studies up to 2000

Talks & Interviews

 * Mar 2017, Leonard Jason's Presentation to European Network on "Current Situation on Prevalence and Diagnostic Crieria for ME and CFS"
 * Jan 2017, Leonard Jason's talk to the Ethical Humanist Society of Chicago on "Understanding Unexplained Illness: From Knowledge to Action"     Slides for "Understanding Unexplained Illness: From Knowledge to Action"
 * 2016, Leonard Jason's comments at Sept. 27th, 2016 #millionsmissing protest in Chicago
 * 2016, 12th International IACFS/ME Biennial Clinical and Research Conference, Emerging Science and Clinical Care, Behavioral Assessment and Treatment of ME/CFS and Fibromyalgia(Workshop given with Fred Friedberg, Ph.D.)
 * 2016 - "qEEG LORETA CFS Case study - Sci Forschen Inc." with Leonard Jason, Marcie Zinn, and Mark Zinn
 * Oct 2015, Defining essential features of myalgic encephalomyelitis and chronic fatigue syndrome (Sweden)]
 * 2015, DePaul Chili Challenge video
 * 2014, Leonard Jason answering questions from members of the Institute of Medicine panel on case definition issues

Invest in ME International ME Conference

 * 2010, Speaker at the 5th Invest in ME International ME Conference on Key Note Speech: How Case Definitions Can Stigmatize: Implications for Epidemiology, Etiology, and Pathophysiology DVD available
 * 2008, Speaker at the 3rd Invest in ME International ME Conference on Case Definitions of ME/CFS – including paediatric case definition DVD available

ME/CFS Alert

 * 2011, ME/CFS Alert Episode 10 - Dr. Leonard Jason, Pt. 3
 * 2011, ME/CFS Alert Episode 09 - Dr. Leonard Jason, Pt. 2
 * 2011, ME/CFS Alert Episode 08 - Dr. Leonard Jason, Pt. 1

Web seminars Science for Patients / Wetenschap voor patienten (The Netherlands, english spoken, dutch subtitles)

 * 2014, 50. Introduction - Experience with ME / Introductie - Ervaring met ME Prof. Leonard Jason
 * 2014, 51. Criteria and Diagnosis part 1 / Criteria en diagnose deel 1 - Prof. Leonard Jason
 * 2014, 52. Criteria and Diagnosis part 2 / Criteria en diagnose deel 2 - Prof. Leonard Jason
 * 2014, 53. ME versus Psychiatric Disorders / ME versus psychiatrische aandoeningen - Prof. Leonard Jason
 * 2014, 54. Treating and managing ME / Behandelen van en omgaan met ME -Prof. Leonard Jason
 * 2014, 55. Symptoms of ME and treatments / Symptomen van ME en behandelingen - Prof. Leonard Jason
 * 2014, 56. Population and Social Impact / Populatie en sociale gevolgen - Prof. Leonard Jason
 * 2014, 57. Future and Teaching about ME / Toekomst en onderwijs geven over ME - Prof. Leonard Jason

Books

 * 2008, Fatigue Science for Human Health, edited by Yatanabe, Y., Evengard, B., Natelson, B.H., Jason, L.A., & Kuratsune, H.
 * 2003, The Handbook of Chronic Fatigue Syndrome by Leonard Jason, Patricia Fennell and Renée R. Taylor.
 * 2001, Clinician's Guide To Controversial Illnesses: Chronic Fatigue Syndrome, Fibromyalgia, and Multiple Chemical Sensitivities, by Renée R. Taylor, Fred Friedberg, and Leonard A. Jason
 * 1998, Understanding Chronic Fatigue Syndrome: An Empirical Guide to Assessment and Treatment, by Fred Friedberg and Leonard Jason

Online Presence

 * Website
 * Twitter

Learn More

 * Wikipedia - Leonard Jason
 * Leonard Jason's Home Page at DePaul University