Environmental Education Project (Portland, Or.). (1978). Clearing. Environmental Education Project.
Chicago-čujuhus (17. p.)Environmental Education Project (Portland, Or.). Clearing. Portland, Or.: Environmental Education Project, 1978.
MLA-čujuhus (9. p.)Environmental Education Project (Portland, Or.). Clearing. Environmental Education Project, 1978.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.