Name	Info	Provider	Link
	subscription/membership/fee required	Ediciones Doyma, S.L.	http://www.elsevier.es/en/linksolver/ft/pii/S0033-8338(20)30120-X
	subscription/membership/fee required	Elsevier Science	https://linkinghub.elsevier.com/retrieve/pii/S0033-8338(20)30120-X