"President Bush Signs HR-1195" (Press release). The White House. June 6, 2008. Archived from the original on October 25, 2017. Retrieved September 1, 2017.
Weingroff, Richard (July 16, 2013) [1998]. "Part I: History". The Dwight D. Eisenhower System of Interstate and Defense Highways. Federal Highway Administration. Archived from the original on June 7, 2021. Retrieved August 18, 2013.
Staff. "Interstate 69 Shreveport to El Dorado". Arkansas Highway and Transportation Department and Louisiana Department of Transportation and Development. Archived from the original on March 20, 2003. Retrieved August 31, 2007.
Michigan Department of Transportation (1984). Say Yes to Michigan!: Official Transportation Map (Map). c. 1:190,080. Lansing: Michigan Department of Transportation. Flint inset. OCLC12701177. Retrieved October 17, 2019 – via Michigan History Center.
Special Committee on U.S. Route Numbering (May 19, 2012). "Report to SCOH"(PDF) (Report). Washington, DC: American Association of State Highway and Transportation Officials. Archived from the original(PDF) on June 3, 2019.
Public Roads Administration (1939). Proposed Interregional Highway System (Map). Scale not given. Washington, DC: Public Roads Administration. Archived from the original on January 2, 2016. Retrieved February 27, 2016 – via Wikimedia Commons.
Public Roads Administration. National System of Interstate Highways, August 2, 1947 (Map). Scale not given. Washington, DC: Public Roads Administration. Archived from the original on October 29, 2013. Retrieved October 25, 2013 – via Wikimedia Commons.
Federal Highway Administration (October 1, 1970). The National System of Interstate and Defense Highways (Map). Scale not given. Washington, DC: Federal Highway Administration. Archived from the original on October 29, 2013. Retrieved October 25, 2013 – via Wikimedia Commons.
Weingroff, Richard (July 16, 2013) [1998]. "Part I: History". The Dwight D. Eisenhower System of Interstate and Defense Highways. Federal Highway Administration. Archived from the original on June 7, 2021. Retrieved August 18, 2013.
"President Bush Signs HR-1195" (Press release). The White House. June 6, 2008. Archived from the original on October 25, 2017. Retrieved September 1, 2017.
Special Committee on U.S. Route Numbering (May 19, 2012). "Report to SCOH"(PDF) (Report). Washington, DC: American Association of State Highway and Transportation Officials. Archived from the original(PDF) on June 3, 2019.
Staff. "Interstate 69 Shreveport to El Dorado". Arkansas Highway and Transportation Department and Louisiana Department of Transportation and Development. Archived from the original on March 20, 2003. Retrieved August 31, 2007.
Public Roads Administration (1939). Proposed Interregional Highway System (Map). Scale not given. Washington, DC: Public Roads Administration. Archived from the original on January 2, 2016. Retrieved February 27, 2016 – via Wikimedia Commons.
Public Roads Administration. National System of Interstate Highways, August 2, 1947 (Map). Scale not given. Washington, DC: Public Roads Administration. Archived from the original on October 29, 2013. Retrieved October 25, 2013 – via Wikimedia Commons.
Federal Highway Administration (October 1, 1970). The National System of Interstate and Defense Highways (Map). Scale not given. Washington, DC: Federal Highway Administration. Archived from the original on October 29, 2013. Retrieved October 25, 2013 – via Wikimedia Commons.
Michigan Department of Transportation (1984). Say Yes to Michigan!: Official Transportation Map (Map). c. 1:190,080. Lansing: Michigan Department of Transportation. Flint inset. OCLC12701177. Retrieved October 17, 2019 – via Michigan History Center.