"United States Census, 1910," index and images, FamilySearch (https://familysearch.org/pal:/MM9.1.1/M2TM-1TP : accessed 30 Sep 2012), Bart Martena in household of Henry Martena, Linn, Audrain, Missouri; citing sheet 6B, family 55, NARA microfilm publication T624, FHL microfilm 1374780.