"United States Census, 1900," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MM5G-B4S : accessed 21 April 2018), Carl Mattoon in household of Newton Mattoon, Lower Boise, Middleton Precincts, Canyon, Idaho, United States; citing enumeration district (ED) 134, sheet 4A, family 73, NARA microfilm publication T623 (Washington, D.C.: National Archives and Records Administration, 1972.); FHL microfilm 1,240,232.
"United States Census, 1910," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:MLH5-M12 : accessed 21 April 2018), Carl N Mattoon in household of Newton T Mattoon, Cold Springs, Nez Perce, Idaho, United States; citing enumeration district (ED) ED 214, sheet 1B, family 16, NARA microfilm publication T624 (Washington D.C.: National Archives and Records Administration, 1982), roll 226; FHL microfilm 1,374,239.
"Idaho, County Marriages, 1864-1950," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:F3TP-X2J : 10 December 2017), Carl Mattoon and Agnes Sartain, 28 Feb 1920; citing Nez Perce, Idaho, various county courthouses, Idaho; FHL microfilm 1,516,570.
"United States World War II Army Enlistment Records, 1938-1946," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:K8BZ-1KB : 5 December 2014), Carl N Mattoon, enlisted 20 Aug 1942, Portland, Oregon, United States; citing "Electronic Army Serial Number Merged File, ca. 1938-1946," database, The National Archives: Access to Archival Databases (AAD) (http://aad.archives.gov : National Archives and Records Administration, 2002); NARA NAID 126323, National Archives at College Park, Maryland.