^Cheney BV, Szmuszkovicz J, Lahti RA, Zichi DA (December 1985). "Factors affecting binding of trans-N-[2-(methylamino)cyclohexyl]benzamides at the primary morphine receptor". Journal of Medicinal Chemistry. 28 (12): 1853–64. doi:10.1021/jm00150a017. PMID2999404.