APA (7th ed.) Citation

Institute of Business Science, International Correspondence Schools, & Stratton, C. (1923). The key to good letter writing. Institute of Business Science.

Chicago Style (17th ed.) Citation

Institute of Business Science, International Correspondence Schools, and Clarence Stratton. The Key to Good Letter Writing. Scranton, Penn: Institute of Business Science, 1923.

MLA (9th ed.) Citation

Institute of Business Science, et al. The Key to Good Letter Writing. Institute of Business Science, 1923.