“Co-administration of Nimodipine with Morphine in Rat, delayed the development of tolerance to analgesic effect of Morphine: The Tail-Flick test study: New insight for treatment of chronic pain”, Int Jour of Biomed Res, vol. 6, no. 10, pp. 786–793, Oct. 2015, doi: 10.7439/ijbr.v6i10.2261.