Name	Info	Provider	Link
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21461286/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/21461286
	free resource	Korean Urological Association	https://www.icurology.org/DOIx.php?id=10.4111/kju.2011.52.3.206