Noronha-Blob L, Kachur JF. Enantiomers of oxybutynin: in vitro pharmacological characterization at M1, M2 and M3 muscarinic receptors and in vivo effects on urinary bladder contraction, mydriasis and salivary secretion in guinea pigs, Journal of Pharmacology and Experimental Therapeutics, 256, S. 562–567, 1991; PMID1993995.