R. K. K, C. sekhar U, V. K. CH, R. reddy PDV, H. P, and C. G, “STABILITY INDICATING VALIDATED METHOD FOR THE SIMULTANEOUS ESTIMATION OF DROTAVERINE HCL AND MEFENAMIC ACID IN PURE AND PHARMACEUTICAL DOSAGE FORM BY RP-HPLC ”, ijprls, vol. 1, no. 2, pp. 59 - 71, Apr. 2013.