Kara G. Mediaeval Mongol Documents from Khara Khoto and East Turkestan in the St. Petersburg Branch of the Institute of Oriental Studies // Manuscripta Orientalia. Vol. 9, No. 2, June 2003. P. 3—40.
As is well known, Qaraqota or Khara Khoto ‘the Black City’ (Heichengzi in modem Chinese) is the presumably late Mongol name of the “dead city” on the Etsin-gol in the Gobi, the ruins of a mediaeval Tangut/Xi Xia fortified city, first explored by P. K. Kozlov, who discovered there a large amount of Xi Xia and other monuments, including some Mongolian prints and manuscripts...