Fragments of Stone Sculptures from Igbomina
- In 1933, H. G. Ramshaw, the CMS School Inspector for the Oro area, informed the public of the presence of stone figures in the area. Over 800 pieces of carved stone, mostly representing human figures, are located at Esie in western Igbomina.
- http://antiquity.ac.uk/ProjGall/usman/index.html

Archaeology in Northeastern Nigeria
- Study from the University of Frankfurt which examines what archaeological discoveries in northeastern Nigeria have revealed about the history and culture of the area.
- http://www.informatik.uni-frankfurt.de/~sfb268/c7/tc7.htm