"Front-Line Duty"(PDF). Findings. Vol. 18, no. 1. University of Michigan School of Public Health. July 1, 2002. p. 30. Archived from the original(PDF) on October 29, 2015. Retrieved September 17, 2019.
"Front-Line Duty"(PDF). Findings. Vol. 18, no. 1. University of Michigan School of Public Health. July 1, 2002. p. 30. Archived from the original(PDF) on October 29, 2015. Retrieved September 17, 2019.