“Natural History of the Bird-Voiced Treefrog (Hyla Avivoca) and Green Treefrog (Hyla Cinerea) in Southern Illinois”. Illinois Natural History Survey Bulletin 36, no. 1-5 (September 30, 1999): 37–66. Accessed May 5, 2024. https://iopn.library.illinois.edu/journals/inhs/article/view/124.