Bahtiar, Yulitas, Marisi Manurung, Manihar Marbun, Iskandar Lubis, and Bistok Saing. 2019. “Head Circumference Features of Under One Year Old Children at Dr. Pirngadi Hospital Medan”. Paediatrica Indonesiana 32 (7-8), 184-9. https://doi.org/10.14238/pi32.7-8.1992.184-9.