"United States Census, 1880," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MNW5-CSG : 14 July 2016), Alexander Black, North, Sharp, Arkansas, United States; citing enumeration district ED 187, sheet 80D, NARA microfilm publication T9 (Washington D.C.: National Archives and Records Administration, n.d.), roll 0057; FHL microfilm 1,254,057.
"United States Census, 1870," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MNCF-36C : 17 October 2014), Alexander Black, Arkansas, United States; citing p. 3, family 13, NARA microfilm publication M593 (Washington D.C.: National Archives and Records Administration, n.d.); FHL microfilm 545,564.