* {{en icon}} {{citatcite knjigabook|prezimelast=Madelung|imefirst=Wilferd|naslovauthorlink=Wilferd Madelung|title=Gīlān iv. History in the Early Islamic Period|serijaseries=[[Encyclopædia Iranica]]|lokacijapublisher=[[Columbia University]]|location=New York|url=http://www.iranica.com/articles/gilan-iv|datumdate=15. 12. 2001.}}