APA (7e ed.) Bronvermelding
(1994). Project learning tree: Environmental education activity guide (2nd.). Project Learning Tree.
Chicago (17e ed.) Bronvermelding
Project Learning Tree: Environmental Education Activity Guide. 2nd. Washington: Project Learning Tree, 1994.
MLA (9e ed.) Bronvermelding
Project Learning Tree: Environmental Education Activity Guide. 2nd. Project Learning Tree, 1994.
Let op: Deze citaties zijn niet altijd 100% accuraat.