1. Callahan, Clark and Kellough (2005). Teaching in the Middle and Secondary Schools. Prentice Hall; 8 edition.
2. Cotton, K. (1988). Classroom questioning. Retrieved June 23, 2004, from http://www.nwrel.org/scpd/sirs/3/cu5.html.
3. Cotton, K. (2001). Classroom questioning. North West Regional Educational Laboratory. Cox, S. & A. Griffith (2007). Outstanding teaching.
4. Davis, B.G. (1993).Tools for teaching. By Jossey-Bass Inc, Publishers, 350 Sansome Street, Sanfrancisco, California 94104.
5. Elder, L. & R. Paul (2002). The miniature guide to the art of asking essential questions. Santa Rosa, CA: Foundation for Critical Thinking.