More research help? (African history/myth/folklore)

Okay, can any of you kind folks point me toward any resources about the Ndwandwe of Southern Africa? I know that they were a rival nation that were defeated by the Zulu, and that they were dispersed and fell apart as a nation at that point (though their descendants can still be traced to a number of other nations/peoples in the region).

What I’m looking for, specifically, is anything on the culture, religion, and folklore of the Ndwandwe. (Something substantially more comprehensive than the tiny Wikipedia entry, I mean.) Or, if such things simply have never been recorded, I need an expert who can assure me that there are no such records, and that I can thus safely make certain reasonable/respectful assumptions for purposes of fiction. (Said assumptions being that they most likely shared the bulk of the religion/folklore with the other Nguni tribes, such as the Zulu.)

Anyone know where to look, or of any specific experts who could answer said question?