Information Retrieval 9th Russian Summer School, RuSSIR 2015, Saint Petersburg, Russia, August 24-28, 2015, Revised Selected Papers - Braslavski, Pavel; Markov, Ilya; Pardalos, Panos; Volkovich, Yana; Ignatov, Dmitry I.; Koltsov, Sergei; Koltsova, Olessia (Springer International Publishing : Imprint: Springer, 2016)