《资治通鉴·唐纪·唐纪四十》
壬申，回纥又派遣使者赤心带了一万匹马前来请求与唐朝贸易。
壬申，回纥复遣使者赤心以马万匹来求互市。
On Renshen [the 9th day of the 9th month], the Uighur Khanate sent another envoy, Chixin, with 10,000 horses, to request to trade with the Tang Dynasty.