Gaya APA

Cunningham, W, P., Cunningham, M, A. (2015). Environmental Science: a global concern thirteenth edition (thirteenth edition). New York: McGraw-Hill Education.

Gaya MLA

Cunningham, William, P.., Cunningham, Mary, Ann. "Environmental Science: a global concern thirteenth edition". thirteenth edition New York: McGraw-Hill Education, 2015. ML.