Cita APA (7a ed.)
Helling, P. (1992). The grammar and proofreading course. American Management Association.
Cita Chicago Style (17a ed.)
Helling, Pam. The Grammar and Proofreading Course. [Saranac Lake, N.Y.]: American Management Association, 1992.
Cita MLA (9a ed.)
Helling, Pam. The Grammar and Proofreading Course. American Management Association, 1992.
Precaución: Estas citas no son 100% exactas.