《后汉书·列传·方术列传下》
年少时游太学，与同乡人任安名声相等，都与同郡杨厚学习图谶之学。
少游太学，与乡人任安齐名，俱事同郡杨厚，学图谶。
In his youth, he went to study at the Tai Xue University, where he became equally famous as his fellow countryman Ren An. Both of them studied diagrams and prophecies from Yang Hou of the same county.