"United States Social Security Death Index," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:JBTM-422 : 7 January 2021), Sidor Belarsky, Jun 1975; citing U.S. Social Security Administration, Death Master File, database (Alexandria, Virginia: National Technical Information Service, ongoing).
"New York, Southern District, U.S District Court Naturalization Records, 1824-1946", database with images, FamilySearch (https://www.familysearch.org/ark:/61903/1:1:7TRC-R6N2 : 8 March 2021), Sidor or Israel Belarsky or Lifschitz, 1938.
"Brasil, Cartões de Imigração, 1900-1965," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:VJ15-PKF : 4 March 2021), Sidor Belarsky, Immigration; citing 1945, Arquivo Nacional, Rio de Janeiro (National Archives, Rio de Janeiro).
"Brasil, Cartões de Imigração, 1900-1965," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:VRQN-18Z : 4 March 2021), Sidor Belarsky, Immigration; citing 1954, Arquivo Nacional, Rio de Janeiro (National Archives, Rio de Janeiro).