《宋书·志·卷二十八》
大明四年六月壬寅曰，皇帝巡视籍田，白龟出现于籍田中，尚书右仆射刘秀之将它献给朝廷。
大明四年六月壬寅，车驾幸籍田，白龟见于千亩，尚书右仆射刘秀之以献。
On June Renyin in the fourth year of Daming period, when the emperor was inspecting the Jitian fields, a white tortoise appeared in the fields, and Minister of the Right Liu Xiu presented it to the imperial court.