Rika Alamsyah, Lina Natamiharja, and Rizka Handayani. 2012. “HUBUNGAN KEBIASAAN MEROKOK DENGAN STATUS PERIODONTAL TUKANG BECAK DI SEKITAR KAMPUS USU MEDAN: RELATIONSHIP BETWEEN SMOKING AND PERIODONTAL STATUS OF PEDICAP RIDER AROUND USU CAMPUS MEDAN”. Dentika: Dental Journal 17 (2):128 -33. https://doi.org/10.32734/dentika.v17i2.1757.