Berk, R. (1974). Collective behaviour. W.M.C Brown Company.
Chicago-čujuhus (17. p.)Berk, Richard. Collective Behaviour. NULL: W.M.C Brown Company, 1974.
MLA-čujuhus (9. p.)Berk, Richard. Collective Behaviour. W.M.C Brown Company, 1974.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.