Name	Info	Provider	Link
	subscription/membership/fee required	Ingenta plc	https://www.ingentaconnect.com/openurl?genre=article&issn=1389-2029&volume=11&issue=3&spage=162&aulast=Boettcher
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/21037854/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/21037854
Cited by Patents in	free resource	The Lens - Patent Citations	https://www.lens.org/lens/search/patent/list?q=citation_id:21037854