Cita APA (7a ed.)

Christophersen, P., & Sandved, A. O. (1970). An Advanced English Grammar. Macmillan.

Cita Chicago Style (17a ed.)

Christophersen, Paul, y Arthur O. Sandved. An Advanced English Grammar. Hampshire [England]: Macmillan, 1970.

Cita MLA (9a ed.)

Christophersen, Paul, y Arthur O. Sandved. An Advanced English Grammar. Macmillan, 1970.