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Based on the sources;

• Ādharbāyjān, Encyclopaedia Islamica Online [1] - "Ādharbāyjān, a region in north-west Iran (at the present time lat. 35°45’ to 40°39’N, long. 44°5’ to 48°50’E) with an area of 109,074 square kilometres (Sāzmān-i Barnāmah, 3), 6 per cent of the total area of Iran. It borders the Republic of Azerbaijan to the north, Turkey and Iraq to the west, the Republic of Azerbaijan and Gīlān to the east, and the Iranian provinces of Zanjān and Kurdistān to the south. Ādharbāyjān constitutes a distinct geographical region; politically it is divided into the provinces of East Ādharbāyjān and West Ādharbāyjān."
• Adurbadagan during the late Sasanian period: A study in administrative geography by Mehrdad Ghodrat-Dizaji
• Northern Territories of the Sasanian Atropatene and the Arab Azerbaijan by Arsen Shahinyan
• The Iranian Expanse by Canepa
• Cambridge History of Iran vol 3 part 1 and 2
• A Reinterpretation of the Sasanian Relief at Salmas by Ehsan Shavarebi
• Ibn Khurradadhbih, Abu al-Qasim 'Abd Allah. Kitab al-Masalik wa'l-Mamalik. Ed and trans. M.J. de Goeje. Leiden: E.J. Brill, 1889.
• Le Strange, Guy. The Lands of the Eastern Caliphate: Mesopotamia, Persia, and Central Asia, from the Moslem conquest to the time of Timur. Cambridge: Cambridge University Press, 1905.
• Bosworth, C.E. "Zand̲j̲ān." The Encyclopaedia of Islam, New Edition, Volume XI: W–Z. Leiden: E. J. Brill, 2002 pp. 446–447.
• Minorsky, M. "Adharbaydjan." The Encyclopaedia of Islam, Vol I. New Edition. Leiden: E.J. Brill, 1960. ISBN 90-04-08114-3.
• Al-Tabari, Abu Ja'far Muhammad ibn Jarir. The History of al-Tabari. Ed. Ehsan Yar-Shater. 40 vols. Albany, NY: State University of New York Press, 1985-2007.