Minoru Nakayama Satoru Kikuchi Hiroh Yamamoto Analysis of lexical features of online postings during a blended learning course. 1-5 2019 ITHET https://doi.org/10.1109/ITHET46829.2019.8937333 conf/ithet/2019 db/conf/ithet/ithet2019.html#NakayamaKY19