APA (7th ed.) Citation

Blankertz, D. F., Ferber, R., & Wales, H. G. (1954). Cases and problems in marketing research. Ronald.

Chicago Style (17th ed.) Citation

Blankertz, Donald F., Robert Ferber, and Hugh G. Wales. Cases and Problems in Marketing Research. New York: Ronald, 1954.

MLA (9th ed.) Citation

Blankertz, Donald F., et al. Cases and Problems in Marketing Research. Ronald, 1954.