Name	Info	Provider	Link
	subscription/membership/fee required	Elsevier Science	https://linkinghub.elsevier.com/retrieve/pii/0002-8703(89)90207-X
Pacemakers and Implantable Defibrillators	free resource	MedlinePlus Health Information	https://medlineplus.gov/pacemakersandimplantabledefibrillators.html