PFEIFFER J W. (1980). 1980 ANNUAL HANDBOOK FOR GROUP FACILITATORS. HUMAN REL. TRAINING.
Lua i Stíl Chicago (17ú heag.)PFEIFFER J W. 1980 ANNUAL HANDBOOK FOR GROUP FACILITATORS. CALIFORNIA: HUMAN REL. TRAINING, 1980.
Lua MLA (9ú heag.)PFEIFFER J W. 1980 ANNUAL HANDBOOK FOR GROUP FACILITATORS. HUMAN REL. TRAINING, 1980.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.