Exposing Paid Opinion Manipulation Trolls Todor Mihaylov author Ivan Koychev author Georgi Georgiev author Preslav Nakov author 2015-09 text Proceedings of the International Conference Recent Advances in Natural Language Processing Ruslan Mitkov editor Galia Angelova editor Kalina Bontcheva editor INCOMA Ltd. Shoumen, BULGARIA Hissar, Bulgaria conference publication mihaylov-etal-2015-exposing https://aclanthology.org/R15-1058/ 2015-09 443 450