Name	Info	Provider	Link
	subscription/membership/fee required	Ingenta plc	https://www.ingentaconnect.com/openurl?genre=article&issn=&volume=38&issue=1&spage=161&aulast=Fokas
	subscription/membership/fee required	Spandidos Publications	https://www.spandidos-publications.com/ijo/38/1/161