CPRE. (1997). water a book of facts and activities.
Chicago ZitierstilCPRE. Water a Book of Facts and Activities. Chennai, C P R Environmental Education Centre, 1997.
MLA ZitierstilCPRE. Water a Book of Facts and Activities. 1997.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.