P. K. Gupta and V. Chaturvedi, “A STUDY ON FORCED DEGRADATION AND VALIDATION OF STABILITY INDICATING RP-HPLC METHOD FOR DETERMINATION OF BENZALKONIUM CHLORIDE IN AZELASTINE HYDROCHORIDE PHARMACEUTICAL OPHTHALMIC FORMULATION”, Asian J Pharm Clin Res, vol. 10, no. 11, pp. 374–382, Nov. 2017.