. "2004-04-04Z"^^ . . "Boris Levitan (June 7, 1914 \u2013 April 4, 2004) was a mathematician known in particular for his work on almost periodic functions, and Sturm\u2013Liouville operators, especially, on inverse scattering."@en . . . "Levitan, Boris"@en . . "1914-06-07Z"^^ . "Russian mathematician" . . . "1914Z"^^ . . . . . . . "2004Z"^^ . . "Boris Levitan"@en .