Name	Info	Provider	Link
Flu	free resource	MedlinePlus Health Information	https://medlineplus.gov/flu.html
Cited by Patents in	free resource	The Lens - Patent Citations	https://www.lens.org/lens/search/patent/list?q=citation_id:4858301
	subscription/membership/fee required	Silverchair Information Systems	https://academic.oup.com/aje/article-lookup/doi/10.1093/oxfordjournals.aje.a112007