Ramhadani, Dwi, Afnani Toyibah, & Ari Kusmiwiyati. " Studi Literatur: Efektivitas Birthing Ball Terhadap Nyeri Persalinan." Malang Journal of Midwifery (MAJORY) [Online], 4.1 (2022): 22-31. Web. 7 Dec. 2022