R. Agrawal, и R. Srikant. VLDB '94: Proceedings of the 20th International Conference on Very Large Data Bases, стр. 487--499. San Francisco, CA, USA, Morgan Kaufmann Publishers Inc., (1994)
K. Lang. Proceedings of the 12th International Conference on Machine Learning, стр. 331--339. Morgan Kaufmann publishers Inc.: San Mateo, CA, USA, (1995)