APA

Helmkamp J. G., Imdieke L. F. & Smith R. E. (1989). Principles of accounting. New York: Wiley.

Chicago

Helmkamp John G, Imdieke Leroy F and Smith Ralph Eugene. 1989. Principles of accounting. New York: Wiley.

Harvard

Helmkamp J. G., Imdieke L. F. and Smith R. E. (1989). Principles of accounting. New York: Wiley.

MLA

Helmkamp John G, Imdieke Leroy F and Smith Ralph Eugene. Principles of accounting. New York: Wiley. 1989.