Analysis of information sources in references of the Wikipedia article "Vương quốc Bột Hải" in Vietnamese language version.
開元二年,移安東都護於平州置。天寶二年,移於遼西故郡城置。In the second year of the Kaiyuan era [714], the Andong Protectorate was moved to Ping Prefecture. In the second year of the Tianbao era [743], it was moved to the old commandery seat of Liaoxi.Chú thích có tham số trống không rõ:
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(trợ giúp)越熹靺鞨東北至黑水靺鞨,地方二千里,編戶十余萬,勝兵數萬人。