Cita APA (7a ed.)

(1972). The World of learning, 1971-72 (22nd edition.). Europa.

Cita Chicago Style (17a ed.)

The World of Learning, 1971-72. 22nd edition. London: Europa, 1972.

Cita MLA (8a ed.)

The World of Learning, 1971-72. 22nd edition. Europa, 1972.