United States. Census Office. 6th census, 1840, & United States. National Archives and Records Service. (1967). 1840 census schedules of mines, agriculture, commerce, and manufacturing for Ohio. National Archives, National Archives and Records Service, General Services Administration.
Παραπομπή σε μορφή Chicago (17η εκδ.)United States. Census Office. 6th census, 1840, και United States. National Archives and Records Service. 1840 Census Schedules of Mines, Agriculture, Commerce, and Manufacturing for Ohio. Washington: National Archives, National Archives and Records Service, General Services Administration, 1967.
Παραπομπή σε μορφή MLA (8th εκδ.)United States. Census Office. 6th census, 1840, και United States. National Archives and Records Service. 1840 Census Schedules of Mines, Agriculture, Commerce, and Manufacturing for Ohio. National Archives, National Archives and Records Service, General Services Administration, 1967.