DJVU PDF Luo Yongxian. 1997, "Expanding the Proto-Tai Lexicon–a Supplement to Li (1977)", in The Mon-Khmer Studies Journal, vol. 27, pp. 271-298. cite.

DJVU PDF Luo Yongxian. 1996, "Tonal irregularities in Tai revisited", in The Mon-Khmer Studies Journal, vol. 25, pp. 69-102. cite.