Michael Shilman Percy Liang Paul A. Viola Learning Non-Generative Grammatical Models for Document Analysis. 962-969 2005 conf/iccv/2005 ICCV http://doi.ieeecomputersociety.org/10.1109/ICCV.2005.140 db/conf/iccv/iccv2005-2.html#ShilmanLV05