Guffey, M. E., & Du-Babcock, B. (2014). Essentials of business communication (6th edition, Philippine edition.). Cengage Learning Asia Pte Ltd (Philippine Branch).
Παραπομπή σε μορφή Chicago (17η εκδ.)Guffey, Mary Ellen, και Bertha Du-Babcock. Essentials of Business Communication. 6th edition, Philippine edition. Pasig City: Cengage Learning Asia Pte Ltd (Philippine Branch), 2014.
Παραπομπή σε μορφή MLA (9th εκδ.)Guffey, Mary Ellen, και Bertha Du-Babcock. Essentials of Business Communication. 6th edition, Philippine edition. Cengage Learning Asia Pte Ltd (Philippine Branch), 2014.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.