Siregar, Eka Darmayanti Putri, Arni Amir, and Nuzulia Irawati. “Correlation Between Zinc and Folic Acid Intake With Hemoglobin Levels in Pregnancy ”. Science Midwifery 10, no. 5 (November 21, 2022): 3767–3775. Accessed May 2, 2026. https://midwifery.iocspublisher.org/index.php/midwifery/article/view/896.