I found these to be helpful:
Water Trapping: http://www.dnr.ohio.gov/wildlife/PDF/chpt9.pdf
Land Trapping: http://www.dnr.ohio.gov/wildlife/PDF/chpt10.pdf
Trapping With Snares: http://www.dnr.ohio.gov/wildlife/PDF/chpt11.pdf
Water Trapping: http://www.dnr.ohio.gov/wildlife/PDF/chpt9.pdf
Land Trapping: http://www.dnr.ohio.gov/wildlife/PDF/chpt10.pdf
Trapping With Snares: http://www.dnr.ohio.gov/wildlife/PDF/chpt11.pdf