1. Lecture Notes in Computer Science;A. Guzman-Arenas,2004
2. Lecture Notes in Artificial Intelligence;A. Guzman-Arenas,2004
3. Levachkine, S., Guzman-Arenas, A.: Confusion between hierarchies partitioned by a percentage rule (unpublished manuscript)
4. Levachkine, S., Guzman-Arenas, A.: Hierarchy as a new data type for qualitative variables (submitted to Data and Knowledge Engineering)