Babbie, E. R. (2010). The practice of social research (12th ed.). Wadsworth Cengage Learning.
Cita Chicago (17th ed.)Babbie, Earl R. The Practice of Social Research. 12th ed. Belmont, CA: Wadsworth Cengage Learning, 2010.
Cita MLA (9th ed.)Babbie, Earl R. The Practice of Social Research. 12th ed. Wadsworth Cengage Learning, 2010.
Atenció: Aquestes cites poden no estar 100% correctes.