Rejeki, S., E. Widayati, M. Machmudah, and A. Yanto. “Decreasing Labor Pain through Sacralist Counter-Pressure Therapy Using Tennis Ball in the Mother During the Labor Process”. Open Access Macedonian Journal of Medical Sciences, vol. 9, no. T4, Mar. 2021, doi:10.3889/oamjms.2021.5817.