. . . . "1990-09-26Z"^^ . "1910Z"^^ . . "1910-07-06Z"^^ . . . . "Lothar Collatz (July 6, 1910 \u2013 September 26, 1990) was a German mathematician, born in Arnsberg, Westphalia."@en . . . "German mathematician" . "1990Z"^^ . "Collatz, Lothar"@en . "Lothar Collatz"@en . .