Kramer S.: Structural Regression Trees. In: Proceedings of the Thirteenth
National Conference on Artificial Intelligence (AAAI-96),
AAAI Press/MIT Press, Cambridge, MA, pp.812-819, 1996.
Kramer S. and Widmer G.: Inducing Classification and Regression Trees in First
Order Logic. In Saso Dzeroski and Nada Lavrac, editors, Relational Data Mining,
Springer, Berlin, 2001.