APA (7e ed.) Bronvermelding

Open University (Great Britain). Earth's Physical Resources Course Team. (1973). Resources and systems. Open University Press.

Chicago (17e ed.) Bronvermelding

Open University (Great Britain). Earth's Physical Resources Course Team. Resources and Systems. Milton Keynes: Open University Press, 1973.

MLA (8e ed.) Bronvermelding

Open University (Great Britain). Earth's Physical Resources Course Team. Resources and Systems. Open University Press, 1973.