Collie, j. (2005). Speaking 4 student's book. Kanisius.
Cita Chicago (17th ed.)Collie, joanne. Speaking 4 Student's Book. Kanisius, 2005.
Cita MLA (9th ed.)Collie, joanne. Speaking 4 Student's Book. Kanisius, 2005.
Atenció: Aquestes cites poden no estar 100% correctes.