Shimunek, Andrew (2017). Languages of Ancient Southern Mongolia and North China: a Historical-Comparative Study of the Serbi or Xianbei Branch of the Serbi-Mongolic Language Family, with an Analysis of Northeastern Frontier Chinese and Old Tibetan Phonology. Wiesbaden: Harrassowitz Verlag. ISBN978-3-447-10855-3. OCLC993110372.
