APA

American Petroleum Institute A., . (1991). Naturally occurring benzene, toluene, and xylenes in soils. Washington: American Petroleum Institute, API.

Chicago

American Petroleum Institute API, . 1991. Naturally occurring benzene, toluene, and xylenes in soils. Washington: American Petroleum Institute, API.

Harvard

American Petroleum Institute A., . (1991). Naturally occurring benzene, toluene, and xylenes in soils. Washington: American Petroleum Institute, API.

MLA

American Petroleum Institute API, . Naturally occurring benzene, toluene, and xylenes in soils. Washington: American Petroleum Institute, API. 1991.