APA (7th ed.) Citation

United nations environment programme. (1990). Sand and gravel extraction projects. UNEP.

Chicago Style (17th ed.) Citation

United nations environment programme. Sand and Gravel Extraction Projects. Nairobi: UNEP, 1990.

MLA (8th ed.) Citation

United nations environment programme. Sand and Gravel Extraction Projects. UNEP, 1990.

Warning: These citations may not always be 100% accurate.