S. C. Marapur, D. S. Wali, B. S. Hunasagi, M. Chetankumar, and R. G. Patil, “Formulation and evaluation of transdermal drug delivery system of verapamil hydrochloride”, J. Drug Delivery Ther., vol. 8, no. 6-s, pp. 70–77, Dec. 2018, doi: 10.22270/jddt.v8i6-s.2081.