K.VINOD KUMAR, et al. “RP-HPLC Method Development And Validation For Simultaneous Estimation Of Sulbactam And Cefoperazone In Dosage Form And In Plasma”. International Journal of Pharma and Bio Sciences, vol. 1, no. 4, Dec. 2010, pp. 87-92, https://ijpbs.net/index.php/journal/article/view/146.