《南齐书·列传·卷五十七》
当初，匈奴女子名叫托跋，嫁给李陵为妻，胡人习俗以母亲的名为姓，所以魏人是李睦的后代，魏人十分忌讳这一点，有说是李陵后代的，就被杀死，到这时才改变姓氏。
初，匈奴女名托跋，妻李陵，胡俗以母名为姓，故虏为李陵之后，虏甚讳之，有言其是陵后者，辄见杀，至是乃改姓焉。
In the beginning, a Xiongnu woman named Tuoba married with Li Ling. According to the Hu people’s custom, they took the mother's name as the surname, so the people of Wei are the descendants of Li Mu. The people of Wei were very taboo about this. Those who said they were descendants of Li Ling would be killed. It was not until this time that the surname was changed.