APA

Whiting P. H., . (1964). The five great problems of salesmen and how to solve them. New York: McGraw-Hill.

Chicago

Whiting Percy H, . 1964. The five great problems of salesmen and how to solve them. New York: McGraw-Hill.

Harvard

Whiting P. H., . (1964). The five great problems of salesmen and how to solve them. New York: McGraw-Hill.

MLA

Whiting Percy H, . The five great problems of salesmen and how to solve them. New York: McGraw-Hill. 1964.