Incorporating Bigram Constraints into an LR Table. - Hiroki Imai; Hui Li; Hozumi Tanaka (ROCLING, 1997)

A Method of Incorporating Bigram Constraints into an LR Table and Its Effectiveness in Natural Language Processing. - Hiroki Imai; Hozumi Tanaka (CoNLL, 1998)

Performance Evaluation of a Robust Method for Mathematical Expression Recognition. - Masayuki Okamoto; Hiroki Imai; Kazuhiko Takagi (ICDAR, 2001)

Performance Evaluation of a Mathematical Formula Recognition System with a large scale of printed formula images. - Kazuki Ashida; Masayuki Okamoto; Hiroki Imai; Tsubasa Nakatsuka (DIAL, 2006)