United States. Census Office. 6th Census, 1840, & United States. National Archives and Records Service. (1974). 1840 Census schedules of mines, agriculture, commerce, and manufacturing for Massachusetts. National Archives.
Chicago-referens (17:e uppl.)United States. Census Office. 6th Census, 1840, och United States. National Archives and Records Service. 1840 Census Schedules of Mines, Agriculture, Commerce, and Manufacturing for Massachusetts. Washington, D.C.: National Archives, 1974.
MLA-referens (8:e uppl.)United States. Census Office. 6th Census, 1840, och United States. National Archives and Records Service. 1840 Census Schedules of Mines, Agriculture, Commerce, and Manufacturing for Massachusetts. National Archives, 1974.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.