References
- Ryan AJ, Aliman FL Jr (Editors): Sports Medicine. New York, Academic Press, 1974. p 518
- 47% of Americans say they exercise daily. Minneapolis Tribune. 7 Oct 1977, p 3B
- Sharkey BJ: Physiology of Fitness. Champaign. Ill, Human Kinetics Publishers, 1979, p 114
- Sinclair GD, Goldsmid BC: Scientists nail down racquetball benefits. National Racquetball 6(5):82–84, 1978