https://vocabularyserver.com/unesco/en/ UNESCO Thesaurus UNESCO UNESCO 2015-09-16 en 2015-09-18 17:46:58 Teaching machines 2015-09-18 17:46:58 Self instructional aids https://vocabularyserver.com/unesco/en/xml.php?skosTema=1007https://vocabularyserver.com/unesco/en/xml.php?skosTema=1049https://vocabularyserver.com/unesco/en/xml.php?skosTema=835https://vocabularyserver.com/unesco/en/xml.php?skosTema=1054https://vocabularyserver.com/unesco/en/xml.php?skosTema=998https://vocabularyserver.com/unesco/en/xml.php?skosTema=831https://vocabularyserver.com/unesco/en/xml.php?skosTema=829