APA-ийн эшлэл(7 дахь хэвлэлт)

Environmental Education Project (Portland, Or.). (1978). Clearing. Environmental Education Project.

Чикаго-гийн эшлэл (17 дахь хэвлэлт)

Environmental Education Project (Portland, Or.). Clearing. Portland, Or.: Environmental Education Project, 1978.

MLA -ийн эшлэл (9 дэх хэвлэлт)

Environmental Education Project (Portland, Or.). Clearing. Environmental Education Project, 1978.