Cita APA (7a ed.)

Smart, W. K., McKelvey, L. W., & Gerfen, R. C. (1957). Business letters (4th ed.). Harper.

Cita Chicago Style (17a ed.)

Smart, Walter Kay, Louis William McKelvey, y Richard Conrad Gerfen. Business Letters. 4th ed. New York: Harper, 1957.

Cita MLA (9a ed.)

Smart, Walter Kay, et al. Business Letters. 4th ed. Harper, 1957.