Azis A., A., A. Rasjid, S. Sudijanto, and R. Kurdi. “Optional Immunizations As Parameter of Parent’s Behavioral Change in Health Needs of Their Off-Springs”. Paediatrica Indonesiana, Vol. 19, no. 11-12, June 2017, pp. 265-75, doi:10.14238/pi19.11-12.1979.265-75.