Effects of Adjective Orientation and Gradability on Sentence Subjectivity Vasileios Hatzivassiloglou author Janyce M Wiebe author 2000 text COLING 2000 Volume 1: The 18th International Conference on Computational Linguistics conference publication hatzivassiloglou-wiebe-2000-effects https://aclanthology.org/C00-1044/ 2000