APA引文

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

Chicago Edition Citation

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

MLA引文

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

警告：這些引文格式不一定是100％准確.