Babbie, E. R. (2004). The Practice of social research. Thomson.
Cita Chicago (17th ed.)Babbie, Earl R. The Practice of Social Research. Southbank, Victoria: Thomson, 2004.
Cita MLA (9th ed.)Babbie, Earl R. The Practice of Social Research. Thomson, 2004.
Atenció: Aquestes cites poden no estar 100% correctes.