R. Wille, and R. Wille. Conceptual Structures: Theory, Tools and Applications, volume 1453 of Lecture Notes in Comput. Sci., page 194--208. Springer, (1998)
R. Wille, and R. Wille. Conceptual Structures: Theory, Tools and Applications, volume 1453 of Lecture Notes in Comput. Sci., page 194--208. Springer, (1998)