Started exploring Docear (http://www.docear.org/) that is a "a unique solution to academic literature management, i.e. it helps you
organizing, creating, and discovering academic literature". Downloading, starting it on my 15.10 Ubuntu went without problem. Configuring it to use the recommended PDF viewer application (PDFXCviewer) needed some tweaking, maybe because I installed it with PlayOnLinux.
Configuring it in Docear's preferences at the PDF Management needs the following command given: