《资治通鉴·唐纪·唐纪二十一》
吐蕃又派遣使者请求与唐和好，太后派遣右武卫胄曹参军贵乡人郭元振前去观察情况。
吐蕃复遣使请和亲，太后遣右武卫胄曹参军贵乡郭元振往察其宜。
Tubo again sent an envoy to ask for peace with Tang, and the empress dowager sent Guo Yuanzhen, an official of the right military guard zuo Cao Canyu in Guixiang, to observe the situation.