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.