APA (7e ed.) Bronvermelding

Babbie, E. (1989). The practice of social research (5th.ed.). Wadsworth.

Chicago (17e ed.) Bronvermelding

Babbie, Earl. The Practice of Social Research. 5th.ed. Belmont: Wadsworth, 1989.

MLA (9e ed.) Bronvermelding

Babbie, Earl. The Practice of Social Research. 5th.ed. Wadsworth, 1989.