《后汉书·本纪·皇后纪下》
虞美人，以良家女年十三选入掖庭，生下冲帝，又生下一女为舞阳长公主。
虞美人者，以良家子年十三选入掖庭，又生女舞阳长公主。
Concubine Yu was a daughter of an official's family, selected to the imperial court at the age of thirteen, and gave birth to Emperor Chong as well as Princess Wu Yang.