APA (7e ed.) Bronvermelding

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

Chicago (17e ed.) Bronvermelding

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

MLA (9e ed.) Bronvermelding

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