Pengaruh keberadaan enrichment cermin terhadap perilaku stereotipe beruk macaca nemestrina (linnaeus, 1766) di Yayasan Inisiasi Alam Rehabilitasi Indonesia (YIARI), Bogor = Effects of mirror enrichment existence on pig-tailed macaque macaca nemestrina (linnaeus, 1766) stereotypic behavior at Yayasan Inisiasi Alam Rehabilitasi Indonesia (YIARI), Bogor.