Tampubolon, Emelia A., and Helena Fransysca. “Counseling on the Benefits of Pregnant Gymnastics Against Low Back Pain in Pregnant Women in Environment V, Medan Tuntungan District in 2021”. Science Midwifery, vol. 9, no. 2, Apr. 2021, pp. 517-20, https://midwifery.iocspublisher.org/index.php/midwifery/article/view/394.