Physical activity measures in patients with myalgic encephalomyelitis/chronic fatigue syndrome: correlations between peak oxygen consumption, the physical functioning scale of the SF-36 questionnaire, and the number of steps from an activity meter. - van Campen, C. M. C.; Rowe, Peter C.; Verheugt, Freek W. A.; Visser, Frans C. (Journal of Translational Medicine, 2020)