Gaya APA

ENGER, E, D., Smith, B, F. (2004). Environmental science: a study of interrelation ships (NINTH EDITION). Amerika: McGraw-HillBook .

Gaya MLA

ENGER, Eldon, D., Smith, Bradley, F. "Environmental science: a study of interrelation ships". NINTH EDITION Amerika: McGraw-HillBook , 2004. FAKULTAS ILMU KESEHATAN.