https://vocabularyserver.com/unbis/en/ UNBIS Thesaurus United Nations United Nations 2018-02-19 en 2018-11-29 15:14:54 GAS FIELDS 2018-11-29 15:14:54 NATURAL GAS FIELDS https://vocabularyserver.com/unbis/en/xml.php?skosTema=3987https://vocabularyserver.com/unbis/en/xml.php?skosTema=1554