APA (7th ed.) Citation

Ray, M. L. (1973). Unobtrusive marketing research techniques. Marketing Science Institute.

Chicago Style (17th ed.) Citation

Ray, Michael L. Unobtrusive Marketing Research Techniques. Cambridge, Mass.: Marketing Science Institute, 1973.

MLA (9th ed.) Citation

Ray, Michael L. Unobtrusive Marketing Research Techniques. Marketing Science Institute, 1973.