Cita APA

Robertson, M., & Perkins, W. E. (1974). Practical correspondence for colleges (4th. ed.). Cincinnatis: South-Western.

Citación estilo Chicago

Robertson, Mary, y W. E. Perkins. Practical Correspondence for Colleges. 4th. ed. Cincinnatis: South-Western, 1974.

Cita MLA

Robertson, Mary, y W. E. Perkins. Practical Correspondence for Colleges. 4th. ed. Cincinnatis: South-Western, 1974.