@article{7:11,author={Andrea Passerini and Paolo Frasconi and Luc De Raedt}, Title={Kernels on Prolog Proof Trees: Statistical Learning in the ILP Setting (Special Topic on Inductive Programming)},journal={Journal of Machine Learning Research},volume={7}, url={http://www.jmlr.org/papers/volume7/passerini06a/passerini06a.pdf}}