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
G. Barabucci, и J. Zingoni. Proceedings of the 1st International Workshop on Collaborative Annotations in Shared Environment: metadata, vocabularies and techniques in the Digital Humanities, стр. 3. ACM, (2013)