P. Pawar, R. Goyal, H. Kaur, and N. Singal, “Study of significance of elevated maternal serum β-human chorionic gonadotropin (β-hCG) level in 16 to 20 weeks pregnant women as predictor of hypertensive disorder of pregnancy”, Int J Reprod Contracept Obstet Gynecol, vol. 7, no. 11, pp. 4721–4730, Oct. 2018.