The sunburst shows the Bibliographic ontology specification. This Semantic Web ontology describes the citations and bibliographic references (i.e. quotes, books, articles, etc).
Its structure is a forest composed by 56 classes distributed in 3 distinct trees that respectevely has the following roots: Document, Collection and event.owl#Event.
Modified http://d3js.org/d3.v3.min.js to a secure url
https://d3js.org/d3.v3.min.js
https://wafi.iit.cnr.it/webvis/libs/jigmaps/zip.js
https://wafi.iit.cnr.it/webvis/libs/jigmaps/tree_utils.js