Astuti, K. E. W., M. Murwati, and N. Fitriani. “The Effect of Endorphin Massage on Reducing The Intensity of Back Pain in Third Trimester Pregnant Women: A Systematic Review”. Journal of Maternal and Child Health, vol. 7, no. 2, Mar. 2022, pp. 148-5, doi:10.26911/thejmch.2022.07.02.04.