Punctuation as Implicit Annotations for Chinese Word Segmentation Zhongguo Li author Maosong Sun author 2009-12 text journal article Computational Linguistics continuing MIT Press Cambridge, MA periodical academic journal li-sun-2009-punctuation 10.1162/coli.2009.35.4.35403 https://aclanthology.org/J09-4006/ 2009-12 35 4 505 512