《旧唐书·本纪·卷十》
太子刚刚从平凉出发，有五片云凌空飞翔，白鹤在前面引路，出军之后，有条黄龙从太子所休息的屋上腾空飞去。
上初发平凉，有彩云浮空，白鹤前引，出军之后，有黄龙自上所憩屋腾空而去。
Just as the Crown Prince set out from Pingliang, there were five clouds flying in the sky, and the white crane led the way. After the army set out, a yellow dragon soared from the house where the Crown Prince was resting.