Yi, J. et al. 2013. Efficacy and tolerability of combined medication of two different antimuscarinics for treatment of adults with idiopathic overactive bladder in whom a single agent antimuscarinic therapy failed. Canadian Urological Association Journal. 7, 1-2 (Feb. 2013), E88–92. DOI:https://doi.org/10.5489/cuaj.269.