APA (7th ed.) Citation

Helppie, C. E., Gibbons, J. R., & Pearson, D. W. (1974). Research guide in economics. General Learning Press.

Chicago Style (17th ed.) Citation

Helppie, Charles E., James R. Gibbons, and Donald W. Pearson. Research Guide in Economics. Morristown, N.J: General Learning Press, 1974.

MLA (9th ed.) Citation

Helppie, Charles E., et al. Research Guide in Economics. General Learning Press, 1974.