Name	Info	Provider	Link
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/20827325/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/20827325
	free resource	Korean Academy of Periodontology	https://www.jpis.org/DOIx.php?id=10.5051/jpis.2010.40.4.164