Name	Info	Provider	Link
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21513372/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/21513372
	subscription/membership/fee required	Silverchair Information Systems	https://pubs.aip.org/aip/jcp/article-lookup/doi/10.1063/1.3578684