1. http://www.ehendrick.org/healthy/
2. and , Principles of exercise prescription, Butterworth-Heinemann, Woburn, MA, 2001.
3. , and , Ankle rehabilitation system, U.S. Patent No. 6162189, December 2000.
4. , and , Rutgers Ankle orthopedic rehabilitation interface, Proceedings of the ASME, Dynamic Systems and Control Division, DSC 67 (1999), 305–312.