APA Format
Friis, Robert H. . (). Essentials of... : Introduction: the environment at risk. ( Ket. Lihat halaman 3-26 ) ( Bab. 1 ) . : London: Jones and Bartlett Learning, 2012
MLA Format
Friis, Robert H. . Essentials of... : Introduction: the environment at risk. ( Ket. Lihat halaman 3-26 ) ( Bab. 1 ) . : London: Jones and Bartlett Learning, 2012,
Australian/Harvard Format
Friis, Robert H. . . Essentials of... : Introduction: the environment at risk. ( Ket. Lihat halaman 3-26 ) ( Bab. 1 ) . London: Jones and Bartlett Learning, 2012, 
Warning: These citations may not always be 100% accurate.