Shurter, R. L., & Nichols, F. G. (1948). Effective letters in business. McGraw-Hill Book Co.
Lua i Stíl Chicago (17ú heag.)Shurter, Robert L., agus Frederick George Nichols. Effective Letters in Business. New York: McGraw-Hill Book Co, 1948.
Lua MLA (8ú heag.)Shurter, Robert L., agus Frederick George Nichols. Effective Letters in Business. McGraw-Hill Book Co, 1948.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.