Makoto Haraguchi Yoshiaki Okubo An Extended Branch and Bound Search Algorithm for Finding Top- <i>N</i> Formal Concepts of Documents. 276-288 2006 conf/jsai/2006 JSAI http://dx.doi.org/10.1007/978-3-540-69902-6_24 db/conf/jsai/jsai2006.html#HaraguchiO06