“ANALYSIS OF LIFESTYLE, KNOWLEDGE, ATTITUDE, AND KNOWLEDGE OF WOMEN AGED 20-50 YEARS OLD WITH VITAMIN D DEFICIENCY-INSUFFICIENCY IN NORTH SUMATERA, INDONESIA”, Sumat. Med. J., vol. 1, no. 01, pp. 1–7, Aug. 2017, doi: 10.32734/sumej.v1i01.75.