APA (7th ed.) Citation

Dury, G. H. (1981). An introduction to environmental systems. Heinemann Educational Books.

Chicago Style (17th ed.) Citation

Dury, G. H. An Introduction to Environmental Systems. London ; Exeter, N.H.: Heinemann Educational Books, 1981.

MLA (9th ed.) Citation

Dury, G. H. An Introduction to Environmental Systems. Heinemann Educational Books, 1981.