Gaya APA

Cunningham, W, P. (2005). (PASCA) Environmental Science a Global Concern (Edisi 8). USA: Mc Graw-Hill International Book Company.

Gaya MLA

Cunningham, William, P.. "(PASCA) Environmental Science a Global Concern". Edisi 8 USA: Mc Graw-Hill International Book Company, 2005. .