SU-FMI: System Description for SemEval-2014 Task 9 on Sentiment Analysis in Twitter. - Boris Velichkov; Borislav Kapukaranov; Ivan Grozev; Jeni Karanesheva; Todor Mihaylov; Yasen Kiprov; Preslav Nakov; Ivan Koychev; Georgi Georgiev (SemEval@COLING, 2014)

Fine-Grained Sentiment Analysis for Movie Reviews in Bulgarian. - Borislav Kapukaranov; Preslav Nakov (RANLP, 2015)