Cita APA (7th ed.)

Leedy, P. D., & Ormrod, J. E. (2001). Practical research: Planning and design (7th ed.). Merrill Prentice Hall.

Cita Chicago (17th ed.)

Leedy, Paul D., i Jeanne Ellis Ormrod. Practical Research: Planning and Design. 7th ed. Upper Saddle River, New Jersey: Merrill Prentice Hall, 2001.

Cita MLA (9th ed.)

Leedy, Paul D., i Jeanne Ellis Ormrod. Practical Research: Planning and Design. 7th ed. Merrill Prentice Hall, 2001.