Marte Eva Koelemaij, et al. “Efficacy Of Oral Probiotic Streptococcus Salivarius K12 In The Prevention Of Halitosis (Bad Breath): A Systematic Review”. International Journal of Pharma and Bio Sciences, vol. 12, no. 4, Dec. 2021, pp. 27-34, https://ijpbs.net/index.php/journal/article/view/6948.