Alexandre Termier Yoshinori Tamada Kazuyuki Numata Seiya Imoto Takashi Washio Tomoyuki Higuchi DIGDAG, a First Algorithm to Mine Closed Frequent Embedded Sub-DAGs. 2007 conf/mlg/2007 MLG http://mlg07.dsi.unifi.it/pdf/01_Termier.pdf db/conf/mlg/mlg2007.html#TermierTNIWH07