APA

Shurter R. L., .Effective letters in business. New York: McGraw-Hill Book Comp.

Chicago

Shurter Robert L, .Effective letters in business. New York: McGraw-Hill Book Comp.

Harvard

Shurter R. L., .Effective letters in business. New York: McGraw-Hill Book Comp.

MLA

Shurter Robert L, .New York: McGraw-Hill Book Comp. .