1. Perceived exertion: a note on ‘history’ and methods;Borg;Med and Sci in Sports,1973
2. The effects of handle shape and size on exerted forces;Cochran;Human Factors,1986
3. Epidermal fatigue as a cause of friction blisters;Comaish;Lancet,1974
4. The use of force sensing resistors in ergonomic tool design;Fellows,1989
5. Interlink Electronics, PO Box 40760, 535 E Montecito St, Santa Barbara, CA 93103.