Anderson, Christopher J.; Wikle, Christopher K.; Zhou, Qin; Royle, J. Andrew (April 28, 2005). "Population Influences on Tornado Reports in the United States". Weather and Forecasting. 22 (3). University of Missouri: 571–579. doi:10.1175/WAF997.1. hdl:10355/9070.
Anderson, Christopher J.; Wikle, Christopher K.; Zhou, Qin; Royle, J. Andrew (April 28, 2005). "Population Influences on Tornado Reports in the United States". Weather and Forecasting. 22 (3). University of Missouri: 571–579. doi:10.1175/WAF997.1. hdl:10355/9070.