aFaculty of Public Health, Airlangga University, Surabaya, Indonesia
bPublic Health Study Programme, Faculty of Health, Efarina University, Simalungun, Indonesia
cDepartment of Epidemiology, Faculty of Public Health, Airlangga University, Surabaya, Indonesia
Copyright © 2017 Korea Centers for Disease Control and Prevention
This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).