APA-ийн эшлэл(7 дахь хэвлэлт)

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

Чикаго-гийн эшлэл (17 дахь хэвлэлт)

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

MLA -ийн эшлэл (9 дэх хэвлэлт)

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