Sperry, L., & Hess, L. R. (1974). Contact counseling: Communication skills for people in organizations. Addison-Wesley Publishing Company.
Citazione stile Chigago Style (17a edizione)Sperry, Len, e Lee R. Hess. Contact Counseling: Communication Skills for People in Organizations. Massachusetts: Addison-Wesley Publishing Company, 1974.
Citatione MLA (9a ed.)Sperry, Len, e Lee R. Hess. Contact Counseling: Communication Skills for People in Organizations. Addison-Wesley Publishing Company, 1974.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.