Nicolò Cesa-Bianchi Claudio Gentile Luca Zaniboni Incremental Algorithms for Hierarchical Classification. 31-54 2006 7 Journal of Machine Learning Research http://www.jmlr.org/papers/v7/cesa-bianchi06a.html db/journals/jmlr/jmlr7.html#Cesa-BianchiGZ06