Dilek Durmuş, et al. “COMPARISON OF EFFECTS OF BIOFEEDBACK ASSISTED ISOMETRIC EXERCISE AND ELECTRICAL STIMULATION ON QUADRICEPS STRENGTH IN KNEE OSTEOARTHRITIS”. Archives of Rheumatology, vol. 20, no. 3, Sept. 2005, pp. 001-5, http://anadolupsikiyatri.net/index.php/pub/article/view/173.