DJVU PDF Sprigg, R.K. 1986, "The syllable finals of Tibetan loan words in Lepcha orthography", in Linguistics of the Tibeto-Burman Area, vol. 9, no. 1, pp. 27-46. cite.
DJVU PDF Zhang, L. 1986, "The puzzle of da-drag in Tibetan", in Linguistics of the Tibeto-Burman Area, vol. 9, no. 1, pp. 47-64. cite.