Wiersma, W. (1985). Research methods in education: An introduction (3rd ed., rev. print.). Allyn and Bacon.

Wiersma, William. Research Methods in Education: An Introduction. 3rd ed., rev. print. Boston: Allyn and Bacon, 1985.

Wiersma, William. Research Methods in Education: An Introduction. 3rd ed., rev. print. Allyn and Bacon, 1985.