Name	Info	Provider	Link
	subscription/membership/fee required	Optica Publishing Group	https://opg.optica.org/abstract.cfm?URI=ol-34-20-3235
	free resource	PubMed Central	https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/19838284/
	free resource	Europe PubMed Central	https://europepmc.org/abstract/MED/19838284
Cited by Patents in	free resource	The Lens - Patent Citations	https://www.lens.org/lens/search/patent/list?q=citation_id:19838284