If your research topic pertains to a cultural group, be aware that spellings can vary. As just one example, the Bambara people are also called Bamana.
A simple web search on your group will reveal if they are known by more than one name. Then, when you start searching library resources. try a separate search using each variation.
This may help increase the number of useful sources your find. Compare the different results with bamana masks versus bambara masks.
