Cita APA (7th ed.)

Nation, J. R. (1997). Research methods. Prentice Hall.

Cita Chicago (17th ed.)

Nation, Jack R. Research Methods. Upper Saddle River, N.J: Prentice Hall, 1997.

Cita MLA (9th ed.)

Nation, Jack R. Research Methods. Prentice Hall, 1997.