Marzena Kryszkiewicz Upper Bound on the Length of Generalized Disjunction-Free Patterns. 31-40 2004 conf/ssdbm/2004 SSDBM http://doi.ieeecomputersociety.org/10.1109/SSDBM.2004.72 db/conf/ssdbm/ssdbm2004.html#Kryszkiewicz04