http://aflang.humnet.ucla.edu/Bole/bole.html (全文テキスト(全般))
http://aflang.humnet.ucla.edu/Bole/Papers/gimba_dissertation.pdf (全文テキスト(全般))
Gimba, A. M. (2002). Bole verb morphology. PhD Thesis, UMI, Ann Arbor.