Illick, J. S., & Aughanbaugh, J. E. (1930). Pitch pine in Pennsylvania. Dept. of Forests and Waters.
Lua i Stíl Chicago (17ú heag.)Illick, Joseph S., agus John E. Aughanbaugh. Pitch Pine in Pennsylvania. Harrisburg, Pa.: Dept. of Forests and Waters, 1930.
Lua MLA (8ú heag.)Illick, Joseph S., agus John E. Aughanbaugh. Pitch Pine in Pennsylvania. Dept. of Forests and Waters, 1930.
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