PATEL PARESH U, and PATEL BHAGIRATH M. “DEVELOPMENT AND VALIDATION OF STABILITY INDICATING REVERSE PHASE HIGH PERFORMANCE LIQUID CHROMATOGRAPHIC METHOD FOR ESTIMATION OF LEVONORGESTREL IN BULK DOSAGE FORM”. International Journal of Pharmaceutics and Drug Analysis, vol. 2, no. 4, Apr. 2014, pp. 311-8, https://ijpda.org/index.php/journal/article/view/56.