Marpaung, R.F. and Pinondang Hotria Siregar 2021. The Relationship Of Knowledge About The Hazards Of Smoking With Smoking Behavior In The Teenns In Nagori Gajing Jaya Kab. Simalungun In 2021. Science Midwifery. 10, 1, October (Oct. 2021), 643–646. DOI:https://doi.org/10.35335/midwifery.v10i1, October.610.