Não informado. (1966). Resource Bulletin NC. North Central Forest Experiment Station, Forest Service.
Chicago-viite (17. p.)Não informado. Resource Bulletin NC. Saint Paul, Minn: North Central Forest Experiment Station, Forest Service, 1966.
MLA-viite (8. p.)Não informado. Resource Bulletin NC. North Central Forest Experiment Station, Forest Service, 1966.
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