http://stonelab.osu.edu/_media/stonelab/courses/51/gibbons-andrews-pit.pdf

http://www.conservation-science.com/products/Sci%20Pubs/Boarman%20et%20al%2098-WSB-PIT%20System.pdf

http://www.bio.davidson.edu/people/midorcas/research/Reprints/Dorcas%20and%20Peterson%20-%20in%20press%20-%20Automated%20monitoring%20-%20PARC.pdf