"United States Census, 1900," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:M92K-HBF : accessed 12 October 2019), Mary Haas in household of Joseph Haas, Rapids Township (excl. Cedar Rapids city) Kenwood Park town, Linn, Iowa, United States; citing enumeration district (ED) 87, sheet 15A, family 185, NARA microfilm publication T623 (Washington, D.C.: National Archives and Records Administration, 1972.); FHL microfilm 1,240,443.
"United States Census, 1910," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MGS9-MZR : accessed 12 October 2019), Mary J Haas in household of Joseph Haas, Cedar, Linn, Iowa, United States; citing enumeration district (ED) ED 79, sheet 5A, family , NARA microfilm publication T624 (Washington D.C.: National Archives and Records Administration, 1982), roll 410; FHL microfilm 1,374,423.
"United States Census, 1920," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:M81F-BYF : accessed 12 October 2019), Mary Haas in household of Joseph Haas, Cedar, Linn, Iowa, United States; citing ED 87, sheet 9A, line 17, family 210, NARA microfilm publication T625 (Washington D.C.: National Archives and Records Administration, 1992), roll 499; FHL microfilm 1,820,499.
"Iowa State Census, 1925," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:QKQ3-61XS : 16 March 2018), Mary Niemeier, Linn Township, Linn, Iowa, United States; citing Linn Township, Linn, Iowa, United States, Iowa State Historical Department, Des Moines; FHL microfilm 1,429,416.
"United States Census, 1930," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:XMJT-5VN : accessed 12 October 2019), Marilyn M Niemeier in household of Henry A Niemeier, Marion, Linn, Iowa, United States; citing enumeration district (ED) ED 28, sheet 8B, line 90, family 203, NARA microfilm publication T626 (Washington D.C.: National Archives and Records Administration, 2002), roll 664; FHL microfilm 2,340,399.
"United States Census, 1940," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:KMYK-8CN : 20 August 2019), Joseph Haas, Marion Township, Linn, Iowa, United States; citing enumeration district (ED) 57-29, sheet 13A, line 4, family 261, Sixteenth Census of the United States, 1940, NARA digital publication T627. Records of the Bureau of the Census, 1790 - 2007, RG 29. Washington, D.C.: National Archives and Records Administration, 2012, roll 1175.
Find A Grave, database and images (accessed 12 October 2019), memorial page for Marie Haas (1869–1947), Find A Grave: Memorial #181504937, citing Shiloh Cemetery, Hiawatha, Linn County, Iowa, USA; Maintained by retired dave (contributor 49091193): headstone photo.