Cita APA (7th ed.)

(2001). The Environment encyclopedia and directory (3rd ed.). Europa Publications Limited.

Cita Chicago (17th ed.)

The Environment Encyclopedia and Directory. 3rd ed. London: Europa Publications Limited, 2001.

Cita MLA (9th ed.)

The Environment Encyclopedia and Directory. 3rd ed. Europa Publications Limited, 2001.

Atenció: Aquestes cites poden no estar 100% correctes.