Reinhardt, V., Houser, W. D., Eisele, S. et al. 1988. Behavior responses of unrelated rhesus monkey females paired for the purpose of environmental enrichment. American Journal of Primatology 14, 135-140.

Pair formation technique is described. Eighty-three percent (15/18) of pairs were compatible, with none of the partners showing signs of depression and none inflicting serious injury on the other. Six of seven animals abandoned behavioral disorders within the first four weeks of living together with a companion.