Koopman, F. S., Brehm, M. A., Heerkens, Y. F., Nollet, F., & Beelen, A. (2014). Measuring fatigue in polio survivors: content comparison and reliability of the Fatigue Severity Scale and the Checklist Individual Strength. Journal of Rehabilitation Medicine, 46(8), 761–767. https://doi.org/10.2340/16501977-1838