Britannica, "Istanbul"Αρχειοθετήθηκε 2007-12-18 στο Wayback Machine.: "Until the Turkish Post Office officially changed the name in 1930, however, the city continued to bear the millenary name of Constantinople."
«Kesitler». Osmanlı Web Sitesi (στα Τουρκικά). Ανακτήθηκε στις 31 Ιανουαρίου 2021.
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Britannica, "Istanbul"Αρχειοθετήθηκε 2007-12-18 στο Wayback Machine.: "Until the Turkish Post Office officially changed the name in 1930, however, the city continued to bear the millenary name of Constantinople."