Lessing, Ferdinand (1960). Mongolian-English Dictionary(PDF). University of California Press. Note that this dictionary uses the transliterations c, ø, x, y, z, ai, and ei; instead of č, ö, q, ü, ǰ, ayi, and eyi;: xii as well as problematically and incorrectly treats all rounded vowels (o/u/ö/ü) after the initial syllable as u or ü.[7]