APA (7e ed.) Bronvermelding

Frederick, J. G. (1929). Selling by telephone. Business Bourse Publishers.

Chicago (17e ed.) Bronvermelding

Frederick, J. George. Selling by Telephone. New York: Business Bourse Publishers, 1929.

MLA (8e ed.) Bronvermelding

Frederick, J. George. Selling by Telephone. Business Bourse Publishers, 1929.