Clauson (1972)
An etimological dictionary of pre-thirteenth-century Turkish
p. 18
üç
‘three’; c.i.a.p.a.l. with some variations of the final consonant. Türkü viii and viii ff. common: Uyğ. viii ff., all varieties, common: Xak. xi üç ‘the number three’, hence üç yarma:k ‘three silver coins’ (dirham) Kaş. I 38: xiii ff. Tef., At. noted: xiv Muh. ṯalāṯa ‘three’ u:ç (sic) Mel. 81, 7; 82, 4; Rif. 188: Çağ. xv ff. üç (‘with -ç’) ‘three’ San. 65r. 8: Kom. xiv ‘three’ üç CCG; Gr.: Kıp. xiii ṯalāṯa üç Hou. 22, 3: xiv ditto İd. 8; ṯalāṯa üç (cim) Bul. 12, 10: xv ditto Tuh. 60b. 7; üs (sic as usual for -ç) Kav. 65, 6.