Kierman, Frank, ed. (1974). "Chinese Ways in Warfare, Volume 74". American Council of Learned Societies. Committee on Studies of Chinese Civilization. Military Studies and History. 74. Harvard University, East Asian Research Center: 121 121. ISBN9780674125759.
Kyzlasov, Leonid R. (2010). The Urban Civilization of Northern and Innermost Asia Historical and Archaeological Research(PDF). Curatores seriei VICTOR SPINEI et IONEL CANDEÂ VII. Vol. The Urban Civilization of Northern and Innermost Asia Historical and Archaeological Research. ROMANIAN ACADEMY INSTITUTE OF ARCHAEOLOGY OF IAȘI Editura Academiei Romane - Editura Istros. p. 245. ISBN978-973-27-1962-6. Florilegium magistrorum historiae archaeologiaeque Antiqutatis et Medii Aevi.
Nanqishuvol. 57 "魏虜,匈奴種也,姓托跋氏。[...] 初,匈奴女名托跋,妻李陵,胡俗以母名為姓"; translation: "The Wei barbarians are a kind of Xiongnu, surnamed Tuoba. [...] Initially, a Xiongnu woman named Tuoba [was] wife of Li Ling. The barbarian (ms. 胡 Hu) customarily used their mothers' name as surname."