1. Akinlabi, Akinbiyi and Eno Urua (1993). Foot structure in the Ibibio verb. Ms. Rutgers University and University of Uyo, Nigeria.
2. Syllabification and prosodic templates in Yawelmani
3. Beckman, Jill (1998). Positional Faithfulness. Ph.D. Dissertation, University of Massachusetts, Amherst.
4. Cook, Thomas L. (1969). The Efik consonant system. Seminar paper presented to the Department of Linguistics and Nigerian Languages, University of Ibadan, Ibadan, Nigeria.
5. (1985). An integrated phonology of Efik. Volume 1. PhD. dissertation, University of Leiden, The Netherlands.