Ahangari, Zohreh, Amir Ghassemi, Sayna Shamszadeh, and Mandana Naseri. 2020. “The Effects of Propolis on Discoloration of Teeth”. Journal of Dental School, Shahid Beheshti University of Medical Sciences 31 (1):33-41. https://doi.org/10.22037/jds.v31i1.28642.