McAlpin, David S, Frederick C Lunenburg, and John R Slate. “School Level and Urbanicity Differences in Drilled Plans for Evacuation, Lockdown, and Shelter-in-Place Scenarios: A National Analysis”. American Journal of Education and Learning 8, no. 1 (February 1, 2023): 22–38. Accessed May 2, 2024. https://onlinesciencepublishing.com/index.php/ajel/article/view/844.