Narayana Charyulu R., Denish Bera, Darshan Sakhia, Keyur Manavadaria, and Nisha G Shetty, “Formulation and evaluation of bilayer floating tablets of Diltiazem hydrochloride for bimodal release”, Int. J. Res. Pharm. Sci., vol. 3, no. 2, pp. 301–306, Jun. 2012.