CROCKETT, J. U. (1978). Trees James Underwood Crockett. Time-Life Books.
Lua i Stíl Chicago (17ú heag.)CROCKETT, James Underwood. Trees James Underwood Crockett. Time-Life Books, 1978.
Lua MLA (8ú heag.)CROCKETT, James Underwood. Trees James Underwood Crockett. Time-Life Books, 1978.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.