《后汉书·列传·朱冯虞郑周列传》
二十年，帝东巡，路过小黄，高帝母昭灵后园陵在这里。当时虞延为部督邮，帝令引见，问以园陵之事。
二十年东巡，路过小黄，高帝母昭灵后园陵在焉，时延为部督邮，诏呼引见，问园陵之事。
In the twentieth year, the emperor inspected the east, passing by Xiaohuang. The mausoleum of the emperor's mother Zhaoling was located there. At that time, Yu Yan was the Governor of the prefecture, and the emperor ordered him to introduce it and asked him about the mausoleum.