Utopia Documents is a semantic, scientific, web-enabled PDF reader that is part of the Utopia toolset. Utopia Documents can be downloaded for free.[1][2][3][4][5]
Utopia provides links to web resources and metadata.[6] Although Utopia is a PDF-reader, it bridges the web-connectivity gap with HTML content by making normally static PDFs fully web-enabled (as long as the user is online).
Since June 2, 2014, Utopia Documents changed their license to become open source under GPLv3.