Here is a short overview and comparison of RDF querying with SPARQL and Jena which is presented as follows: 1. SPARQL; 2. SPARQL from inside Jena; 3. Explicit and implicit relations when querying with Jena 4.Querying remote SPARQL endpoitns
{. Hoffmann, and {. Stolze. Schriftenreihe des Lehrstuhls Abfallwirtschaft und des Lehrstuhls Siedlungswasserwirtschaft / Bauhaus-Universität Weimar Rhombos-Verl., Berlin, (2008)