Purbasari, E., O. Erikardo, and R. A. Jasmine. “Relationship of Smoking Habits to The Potential of Hydrogen (pH) of Saliva in Active Smokers”. Jurnal EduHealth, vol. 13, no. 02, Dec. 2022, pp. 881-6, https://ejournal.seaninstitute.or.id/index.php/healt/article/view/933.