@article{Fricke2006,
  author    = {Werner Fricke},
  title     = {The historical and recent evolution in the Sudanic and Sub-Sudanic Savannah of NE-Nigeria: geographical, linguistic and anthropological aspects},
  journal   = {Berichte des Sonderforschungsbereichs 268},
  volume    = {14},
  pages     = {125 -- 126},
  year      = {2006},
}