Cita APA (7a ed.)

Harper,W.M. (1991). c (6th.ed.). Prentice hall.

Cita Chicago Style (17a ed.)

Harper,W.M. C. 6th.ed. London: Prentice hall, 1991.

Cita MLA (9a ed.)

Harper,W.M. C. 6th.ed. Prentice hall, 1991.