Automatic Authorship Attribution E Stamatatos author N Fakotakis author G Kokkinakis author 1999-06 text Ninth Conference of the European Chapter of the Association for Computational Linguistics Henry S Thompson editor Alex Lascarides editor Association for Computational Linguistics Bergen, Norway conference publication stamatatos-etal-1999-automatic https://aclanthology.org/E99-1021/ 1999-06 158 164