Crowley, D. J., & Heyer, P. (1995). Communication in history: Technology, culture, society (2nd ed.). Longman Publishers USA.
Lua i Stíl Chicago (17ú heag.)Crowley, D. J., agus Paul Heyer. Communication in History: Technology, Culture, Society. 2nd ed. White Plains, N.Y: Longman Publishers USA, 1995.
Lua MLA (9ú heag.)Crowley, D. J., agus Paul Heyer. Communication in History: Technology, Culture, Society. 2nd ed. Longman Publishers USA, 1995.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.