Willmore, J. H., Parr, R. B., Haskell, W. L., Costill, D. L., Milburn, L. J., Kerlan, R. K., & Broekhoff, J. (1976). Athletic profile of professional football players. Physical education, sports and the sciences. Papers presented in honor of H. Harrison Clarke, S. 154-168.

Willmore, Jack H., Richard B. Parr, William L. Haskell, David L. Costill, Lloyd J. Milburn, Robert K. Kerlan, and Jan Broekhoff. "Athletic Profile of Professional Football Players." Physical Education, Sports and the Sciences. Papers Presented in Honor of H. Harrison Clarke 1976: S. 154-168.

Willmore, Jack H., et al. "Athletic Profile of Professional Football Players." Physical Education, Sports and the Sciences. Papers Presented in Honor of H. Harrison Clarke 1976: S. 154-168.