Then please do not simply revert but add other sources to it As for the sources in controversial topics the EI and EIr are considered authoritative i e when there is no equally scholastic source available In addition Carter Vaughn Findley is a notable specialist of Turkic studies and the author of the book Turks in World History published by the Oxford University Press in 2005 And his source clearly says Many elements of Non Turkic origin also became part of T rk statecraft for example as in the case of khatun and beg both terms being of Sogdian origin and ever since in common use in Turkish p 45 link to Google Books