Leedy, P. D. (1985). Practical Research: Planning and design (3rd.ed.). Macmillan.
Cita Chicago (17th ed.)Leedy, Paul D. Practical Research: Planning and Design. 3rd.ed. New York: Macmillan, 1985.
Cita MLA (9th ed.)Leedy, Paul D. Practical Research: Planning and Design. 3rd.ed. Macmillan, 1985.
Atenció: Aquestes cites poden no estar 100% correctes.