Unsupervised Part-Of-Speech Tagging with Anchor Hidden Markov Models Karl Stratos author Michael Collins author Daniel Hsu author 2016 text journal article Transactions of the Association for Computational Linguistics continuing MIT Press Cambridge, MA periodical academic journal stratos-etal-2016-unsupervised 10.1162/tacl_a_00096 https://aclanthology.org/Q16-1018/ 2016 4 245 257