Georg Gottlob Gianluigi Greco Zoltán Miklós Francesco Scarcello Thomas Schwentick Tree Projections: Game Characterization and Computational Aspects. 217-226 2009 Graph Theory, Computational Intelligence and Thought http://dx.doi.org/10.1007/978-3-642-02029-2_21 conf/birthday/2009golumbic db/conf/birthday/golumbic2009.html#GottlobGMSS09