B. Shetty, M., K. B. M., M. Malyala, A. Swarup, D. S. Pathadan, and S. Pocha. “Preterm Birth: Associated Risk Factors and Outcome in Tertiary Care Center”. International Journal of Reproduction, Contraception, Obstetrics and Gynecology, vol. 6, no. 8, July 2017, pp. 3271-4, doi:10.18203/2320-1770.ijrcog20173258.