Fraenkel, J. R., & Wallen, N. E. (2009). How to design and evaluate research in education (7th ed.). McGraw-Hill.

Fraenkel, Jack R., and Norman E. Wallen. How to Design and Evaluate Research in Education. 7th ed. New York, NY: McGraw-Hill, 2009.

Fraenkel, Jack R., and Norman E. Wallen. How to Design and Evaluate Research in Education. 7th ed. McGraw-Hill, 2009.