Cita APA (7th ed.)

Christophersen, P., & Sandved, A. O. (1977). An advanced english grammar. Macmillan Education.

Cita Chicago (17th ed.)

Christophersen, Paul, i Arthur O. Sandved. An Advanced English Grammar. Londres: Macmillan Education, 1977.

Cita MLA (9th ed.)

Christophersen, Paul, i Arthur O. Sandved. An Advanced English Grammar. Macmillan Education, 1977.