This lexicon for the Mbule language is part of the linguistic data analyzed by Virginia Boyd for her PhD dissertation. The data is the result of personal research collected during short trips to the Mbule region, and checked with individual Mbule speakers who came to Yaoundé for work sessions from 2009 to 2013.
Mbure is referred to in only a couple of works, notably:
Scruggs. Linguistic survey of the Bokito region (including approximately 180 terms). 1982.
Boone. Survey of Mbule (including approximately 100 terms). 1992b.
Only seven vowels are identified in these works.