Cita APA (7a ed.)

Katzenstein, H., & Sachs, W. S. (1986). Direct marketing. Merrill.

Cita Chicago Style (17a ed.)

Katzenstein, Herbert, y William S. Sachs. Direct Marketing. Columbus [etc]: Merrill, 1986.

Cita MLA (9a ed.)

Katzenstein, Herbert, y William S. Sachs. Direct Marketing. Merrill, 1986.