APA (7e ed.) Bronvermelding

Crowley, W. R. (1997). Chemicals on the Internet: A directory of industry sites. Gulf Pub. Co.

Chicago (17e ed.) Bronvermelding

Crowley, William R. Chemicals on the Internet: A Directory of Industry Sites. Houston, Tex: Gulf Pub. Co, 1997.

MLA (9e ed.) Bronvermelding

Crowley, William R. Chemicals on the Internet: A Directory of Industry Sites. Gulf Pub. Co, 1997.