DJVU PDF Smith, K.D. 1975, "The velar animal prefix in Vietnamese languages", in Linguistics of the Tibeto-Burman Area, vol. 2, no. 1, pp. 1-18. cite.

DJVU PDF Lehman, F.K. 1975, "Wolfenden's non-pronominal a- prefix in Tibeto-Burman", in Linguistics of the Tibeto-Burman Area, vol. 2, no. 1, pp. 19-44. cite.

DJVU PDF Watters, D.E. 1975, "The evolution of a Tibeto-Burman pronominal verb morphology", in Linguistics of the Tibeto-Burman Area, vol. 2, no. 1, pp. 45-79. cite.