APA Style

RYAN, William T. ((,d,)). Principles of Marketing . 3th ed: Learning Systems Company.

Chicago Style

RYAN, William T. Principles of Marketing. 3th ed: Learning Systems Company, (,d,). Text.

MLA Style

RYAN, William T. Principles of Marketing. 3th ed: Learning Systems Company, (,d,). Text.

Turabian Style

RYAN, William T. Principles of Marketing. 3th ed: Learning Systems Company, (,d,). Print.