Here we publish the bibliographic data of the electronic documents - mostly books - in the Hungarian Electronic Library in the form of Linked Open Data. The dataset contains external references to dictionaries and namespaces such as: VIAF, BIBO, GeoNames, SPAR Ontologies, DCMI Type Vocabulary, LCSH and the SKOS implementation of the National Széchényi Library's thesaurus. The metadata can be downloaded in RDF format as a single ZIP package or as separate files, or can be retrieved from the web server through "content negotiation", or searchable in a Virtuoso database with SPARQL language queries. Here is a presentation (in Hungarian) about the semantic web developments of MEK and DKA. More information can be obtained at

Dataset characteristics

(Last updated: June 27, 2019.)
  • Number of documents: 19.067
  • Number of triplets: 1.252.307
  • Number of links to certain external namespaces and dictionaries: 14.769 82.709 71.053 9.305 61.410 19.077 19.077
  • Namespaces and dictionaries
    used for references

    SPARQL Endpoint
    (Virtuoso database)

    Default Data Set Name:

    SPARQL query example
    Dramas, plays published under a Creative Commons license
    PREFIX rdf: 
    PREFIX rdfs: 
    PREFIX bibo: 
    PREFIX dcterms: 
    SELECT distinct ?title ?x ?r
    WHERE { ?x dcterms:type "plays" .
    ?x dcterms:title ?title .
    ?x dcterms:rights ?r .
    FILTER regex(str(?r), "")

    Sample record

    Content negotiation
    (retrieving RDF metadata from the nginx
    webserver via HTTP protocol)

    curl -i -H "Accept: application/rdf+xml"
    HTTP/1.1 303 See Other
    Server: nginx
    Date: Mon, 05 Jan 2015 13:59:19 GMT
    Content-Type: text/html
    Content-Length: 162
    Connection: keep-alive
    Keep-Alive: timeout=5