Titisari, Ira, et al. “Analysis Factors Correlated With the Incidence of Retained Placenta to Vaginal Birth Mother at Aura Syifa Hospital of Kediri Regency”. JURNAL KEBIDANAN, vol. 9, no. 2, Oct. 2020, pp. 97-107, doi:10.35890/jkdh.v9i2.145.