RepFocus
www.repfocus.dk
Mackessy, S.P.
2005
Desert Massasauga ratllesnake (Sistrurus catenatus edwardsii): a technical conservation assessment.
USDA Forest Service, Rocky Mountain Region, Fort Collins. 56 pp. [URL:www.fs.fed.us/r2/projects/scp/assessments/massasauga.pdf].