Gaya APA

Cunningham, W, P., Cunningham, M, A. (2015). Environmental science : a global concern (13th. ed.). New York: McGraw-Hill, Education.

Gaya MLA

Cunningham, William, P.., Cunningham, Mary, Ann. "Environmental science : a global concern". 13th. ed. New York: McGraw-Hill, Education, 2015. Text.