Guffey, Mary Ellen. Essentials of business communication (2nd ed)/ Mary Ellen Guffey, Bertha Du-Babcock - 2nd ed - Singapore: Cengage, 2010 - xix, 556 p. ill. ; 28 cm. Includes index ISBN: 9789814319171 LC Class. No.: HF5718.3 / .G84 2010