Kouichi Sakurai Souichi Furuya Improving Linear Cryptanalysis of LOKI91 by Probabilistic Counting Method. 114-133 http://link.springer.de/link/service/series/0558/bibs/1267/12670114.htm 1997 conf/fse/1997 FSE db/conf/fse/fse97.html#SakuraiF97