Kafadar, Cemal (1995). Between Two Worlds: The Construction of the Ottoman State. էջ xii. «There is still not one authentic written document known from the time of ʿOsmān, and there are not many from the fourteenth century altogether.»
Kermeli, Eugenia (2009). «Osman I». In Ágoston, Gábor; Bruce Masters (eds.). Encyclopedia of the Ottoman Empire. էջ 444. «Reliable information regarding Osman is scarce. His birth date is unknown and his symbolic significance as the father of the dynasty has encouraged the development of mythic tales regarding the ruler's life and origins, however, historians agree that before 1300, Osman was simply one among a number of Turkoman tribal leaders operating in the Sakarya region.»
Imber, Colin (2009). The Ottoman Empire, 1300-1650: The Structure of Power (2 ed.). New York: Palgrave Macmillan. էջ 8.
Kafadar, Cemal (1995). Between Two Worlds: The Construction of the Ottoman State. էջ 129. «Of [military undertakings] we know nothing with certainty until the Battle of Bapheus, Osman's triumphant confrontation with a Byzantine force in 1301 (or 1302), which is the first datable incident in his life.»
