1. Edwards, S. (1993). The Heart Rate Monitor B ook. Sacramento, CA: Fleet Feet Press.
2. Green, M. (1994). Hearts, you lose! Runners World (South African edition), July-August, p. 52.
3. Pfitzinger, P. (1994). Training with heart. Running Times, pp. 64-67.
4. Thomas, J.A. (1988). Drugs, Athletes and Physical Performance, pp. 217-234. New York: Plenum Press.
5. Van Camp, S.P. (1988). Pharmacologic factors in exercise and exercise testing. In Resource M anual for Guidelines for Exercise Training and Prescription (edited by S.N. Blair, P. Painter, R.R. Pate, L.K. Smith and C.B. Taylor), pp. 135-152. Philadelphia, PA: Lea and Febiger.