Collin, S, Nijs, J, Meeus, M, Polli, A, Willekens, B & Ickmans, K 2017, ' Endogenous pain facilitation rather than inhibition differs between people with chronic fatigue syndrome, multiple sclerosis, and controls : an observational study ', Pain Physician, vol. 20, no. 4, pp. E489-E497 . < http://www.painphysicianjournal.com/linkout?issn=1533-3159&vol=20&page=E489 > Pain physician ResearcherID Europe PubMed Central Scopus-Elsevier