Cita APA (7th ed.)

Philip Lief Group, Princeton Language Institute, & Kipfer, B. A. (1993). 21 century manual of style. Laurel.

Cita Chicago (17th ed.)

Philip Lief Group, Princeton Language Institute, i Barbara Ann Kipfer. 21 Century Manual of Style. New York: Laurel, 1993.

Cita MLA (9th ed.)

Philip Lief Group, et al. 21 Century Manual of Style. Laurel, 1993.