Summers, G. W., Peters, W. S., & Armstrong, C. P. (1977). Basic statistics in business and economics (2d ed.). Wadsworth Pub. Co..

Summers, George W., William S. Peters, and Charles P. Armstrong. Basic Statistics in Business and Economics. 2d ed. Belmont, Calif.: Wadsworth Pub. Co., 1977.

Summers, George W., et al. Basic Statistics in Business and Economics. 2d ed. Wadsworth Pub. Co., 1977.