Name	Info	Provider	Link
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/22787532/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/22787532
	free resource	The Korean Society of Echocardiography	https://e-jcvi.org/DOIx.php?id=10.4250/jcu.2012.20.2.114