Fun site with links to articles on many learning theories including Piaget, Constructivism, Behavioralism, Brain Based Learning, Social Cognition, Emotional Inteligence, Social Learning Theory, and more.
Z. Zheng, G. Webb, and K. Ting. Proceedings of the Sixteenth International Conference on Machine Learning (ICML-99), page 493-502. San Francisco, Morgan Kaufmann, (1999)