Bertcher, H. J., & Maple, F. F. (1977). Creating groups. Sage Publications.
Chicago Style aipamenaBertcher, Harvey J., and Frank F. Maple. Creating Groups. Beverly Hills: Sage Publications, 1977.
MLA aipamenaBertcher, Harvey J., and Frank F. Maple. Creating Groups. Sage Publications, 1977.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.