Irufe akiyesi ati iwadii yi ni awon onimo eda-ede n pe geesi re ni "duality" tabi "double articulation" iwadii fihan pe awon eye ati eranko ti won ni iro ede ko po, iye ede ti okookan ni ko po pelu.. 
Atanda (1980) an Introduction to Yorùbá History Ìbàdàn University Press Limited 3.Adeọ Fafásìku (1995) Igbajo And Its People printed By Writers Press Limited 4.G.O.. 