Schmitt 2004, p. 588-590. Schmitt, Rüdiger (2004). «Hydarnes». In: Yarshater, Ehsan. Encyclopædia Iranica Vol. XII, Fasc. 6. Nova Iorque: Encyclopædia Iranica Foundation
Bivar 2002, p. 151-153. Bivar, A. D. H. (2002). «GORGĀN v. Pre-Islamic history». In: Yarshater, Ehsan. Enciclopédia Irânica Vol. XI, Fasc. 2. Nova Iorque: Encyclopædia Iranica Foundation
Schmitt 1989, p. 935-936. Schmitt, Rüdiger (1989). «Amestris». In: Yarshater, Ehsan. Encyclopædia Iranica Vol. Vol. I, Fasc. 9. Nova Iorque: Encyclopædia Iranica Foundation