Akhter, Farkhunda, et al. “RISING FREQUENCY OF PLACENTA PREVIA AND ASSOCIATED MORBIDITY IN WOMEN WITH PREVIOUS CAESAREAN SECTION: Placenta Previa and Previous Caesarean Section”. Pakistan Armed Forces Medical Journal, vol. 65, no. 3, June 2015, pp. 313-7, https://www.pafmj.org/PAFMJ/article/view/879.