APA (7. basım) Alıntı

(1994). Project learning tree: Environmental education activity guide (2nd.). Project Learning Tree.

Chicago Style (17. basım) Atıf

Project Learning Tree: Environmental Education Activity Guide. 2nd. Washington: Project Learning Tree, 1994.

MLA (9th ed.) Atıf

Project Learning Tree: Environmental Education Activity Guide. 2nd. Project Learning Tree, 1994.