Pitch tubes and woodpecker work indicate a tree attacked by bark beetles

Chicago citation style
Department of the Interior. National Park Service. Region II. 8/7/1937-6/1962. Pitch tubes and woodpecker work indicate a tree attacked by bark beetles. 1939. Retrieved from the Digital Public Library of America, http://catalog.archives.gov/id/286073. (Accessed June 18, 2018.)
APA citation style
Department of the Interior. National Park Service. Region II. 8/7/1937-6/1962, (1939) Pitch tubes and woodpecker work indicate a tree attacked by bark beetles. Retrieved from the Digital Public Library of America, http://catalog.archives.gov/id/286073
MLA citation style
Department of the Interior. National Park Service. Region II. 8/7/1937-6/1962. Retrieved from the Digital Public Library of America <http://catalog.archives.gov/id/286073>.
Note: These citations are programmatically generated and may be incomplete.