Fitri, Sari Rahma, and Suriati Lubis. “Knowledge Extension of Pregnant Women About Pregnancy Exercises That Can Reduce Back Pain in the Baru Ladang Bambu Village in 2021”. Science Midwifery, vol. 9, no. 2, Apr. 2021, pp. 530-2, https://www.midwifery.iocspublisher.org/index.php/midwifery/article/view/398.