Berger, M. L., & Berger, P. J. (1972). Group training techniques. Gower Press.
Lua i Stíl Chicago (17ú heag.)Berger, Melvyn Louis, agus Pam J. Berger. Group Training Techniques. [Epping]: Gower Press, 1972.
Lua MLA (9ú heag.)Berger, Melvyn Louis, agus Pam J. Berger. Group Training Techniques. Gower Press, 1972.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.