佛祖統紀 36.67

36.67

In the fourth year, Master Huiyuan, observing that in the region east of the Yangtze scriptures were incomplete, the methods of dhyāna were unheard of, and the Vinayapiṭaka was fragmentary and deficient, sent his disciple Zhi Faling and others to Tianzhu to search for texts. They obtained Sanskrit manuscripts in Khotan, where they encountered Buddhabhadra and invited him to return east with them.