Preston, R. J. (1968). Rocky mountain trees: A handbook of the native species with plates and distributions maps (3a. ed.). Dover.
Chicago-viite (17. p.)Preston, Richard J. Rocky Mountain Trees: A Handbook of the Native Species with Plates and Distributions Maps. 3a. ed. Nueva York: Dover, 1968.
MLA-viite (9. p.)Preston, Richard J. Rocky Mountain Trees: A Handbook of the Native Species with Plates and Distributions Maps. 3a. ed. Dover, 1968.
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