Edwards, J. Michele (20 January 2001). "Roberta Bitgood [Wiersma]". Grove Music Online. Retrieved 15 February 2026.{{cite web}}: CS1 maint: url-status (link)
Wiersma, Grace Claire (1990). A study of the Bai (Minjia) language along historical lines (PhD thesis). University of California at Berkeley. OCLC31052150.