Sakinah, B. I., D. Husada, and S. Sulistiawati. “Risk Factors of Preterm Labor in RSUD Dr. M. Soewandhi Surabaya in 2017”. Journal Of The Indonesian Medical Association, Vol. 69, no. 12, Mar. 2020, pp. 344-8, doi:10.47830/jinma-vol.69.12-2019-165.