《宋史·本纪·卷四》
这个月，舒州献上黑石，有白字为 丙子年出赵号二十一帝 。
是月，舒州上玄石有白文曰 丙子年出赵号二十一帝 。
During the month, black stone was presented from the prefecture of Shuzhou, and it had the inscription: "In the bingzi year, a child named Zhao was the twenty-first emperor."