APA-viite

Ryan, W. T. (1971). Programmed learning aid for principles of marketing. Learning systems company.

Chicago-tyylinen lähdeviittaus

Ryan, William T. Programmed Learning Aid for Principles of Marketing. Illinois: Learning systems company, 1971.

MLA-viite

Ryan, William T. Programmed Learning Aid for Principles of Marketing. Learning systems company, 1971.