Name	Info	Provider	Link
Tears	free resource	MedlinePlus Health Information	https://medlineplus.gov/tears.html
	subscription/membership/fee required	Optica Publishing Group	https://opg.optica.org/abstract.cfm?URI=ao-58-29-7987
Cited by Patents in	free resource	The Lens - Patent Citations	https://www.lens.org/lens/search/patent/list?q=citation_id:31674351