Name	Info	Provider	Link
Full text from AIR - Univ. Milan	free resource	Archivio Istituzionale della Ricerca Unimi	https://air.unimi.it/handle/2434/788029
phosphodiesterase 4A - data and references	free resource	Guide to Pharmacology	https://www.guidetopharmacology.org/GRAC/ObjectDisplayForward?objectId=1300
	free resource	Israel Medical Association	http://www.ima.org.il/IMAJ/ViewArticle.aspx?year=2020&month=06&page=335