Bergadano, FrancescoMatwin, StanMichalski, Ryszard S.Zhang, Jianping2006-11-132006-11-131990-09Bergadano, F., Matwin, S., Michalski, R. S. and Zhang, J., "Learning Two-Tiered Descriptions of Flexible Concepts: The POSEIDON System," Reports of the Machine Learning and Inference Laboratory, MLI 90-10, School of Information Technology and Engineering, George Mason University, Fairfax, VA, September, 1990.https://hdl.handle.net/1920/164926015080 bytesapplication/pdfen-USLearning Two-Tiered Descriptions of Flexible Concepts: The POSEIDON SystemTechnical report