Citazione Stile APA (7a Edizione)

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

Citazione stile Chigago Style (17a edizione)

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

Citatione MLA (9a ed.)

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