Coffman, Robert. "Howard County 9th Grade United States History". OER Commons. Institute for the Study of Knowledge Management in Education, 22 Jun. 2016. Web. 27 Dec. 2024. <https://oercommons.org/authoring/14327-howard-county-9th-grade-united-states-history>.
Coffman, R. (2016, June 22). Howard County 9th Grade United States History. OER Commons. Retrieved December 27, 2024, from https://oercommons.org/authoring/14327-howard-county-9th-grade-united-states-history.