《资治通鉴·汉纪·汉纪五十六》
当时，袁谭属下的各城都已归顺曹操，只有乐安郡太守管统未降。
谭所部诸城皆服，唯乐安太守管统不下。
At that time, all the cities under Yuan Tan had surrendered to Cao Cao, except for the prefect of Le'an County, Guan Tong, who had not surrendered.