. "Anton Kotzig (22 October 1919 \u2013 20 April 1991) was a Slovak\u2013Canadian mathematician, expert in statistics, combinatorics and graph theory. The Ringel-Kotzig conjecture on graceful labeling of trees is named after him and Gerhard Ringel."@en . "1991Z"^^ . . "Canadian mathematician" . "1919Z"^^ . . . "1991-04-20Z"^^ . . . "Anton Kotzig"@en . . . "1919-10-22Z"^^ . . "Kotzig, Anton"@en .