"United States Census, 1910," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/MKPL-WTX : accessed 13 Oct 2014), Albert L Hardin in household of Marion E Hardin, Pike, Marion, Indiana, United States; citing enumeration district (ED) 17, sheet 2A, family 35, NARA microfilm publication T624, FHL microfilm 1374379.
"United States Census, 1930," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/X4YG-4BL : accessed 13 Oct 2014), Albert Hardin, Pike, Marion, Indiana, United States; citing enumeration district (ED) 0250, sheet 9B, family 226, NARA microfilm publication T626, roll 616.
"United States Census, 1940," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/V1YH-BGZ : accessed 13 Oct 2014), Albert Hardin, Pike Township, Marion, Indiana, United States; citing enumeration district (ED) 49-31A, sheet 8A, family 160, NARA digital publication of T627, roll 1076.