Widhani, F. D. P., I. Nosartika, I. A. Kusuma, and Y. B. Prabowo. “Relationship Between Knowledge of Periodontal Disease and Gingival Melanin Pigmentation and Smoking Behavior”. E-GiGi, vol. 10, no. 1, Feb. 2022, pp. 24-31, doi:10.35790/eg.v10i1.37333.