《宋史·本纪·卷二十九》
夏四月初二，寻访征求遗失的历书以及精通星历的人。
夏四月丙午，访求亡逸历书及精于星历者。
On the second day of the fourth month, Xia, search for and solicit lost historical books and people who are proficient in astrology and the calendar.