\bibitem{Grasg} Gras R., Briand H., Peter P. (1996) Structuration sets with implication intensity", Proceedings of the International Conference on Ordinal and Symbolic Data Analysis - OSDA 95, E.Diday, Y.Chevallier, Otto Opitz, Eds., Springer, Paris, 147-156.
\bibitem{Grash} Gras R., Briand H., Peter P., Philippé J. (1997) Implicative statistical analysis, Proceedings of International Congress I.F.C.S., 96, Kobé, Springer-Verlag, Tokyo , 1997, 412-419
\bibitem{Grasg} Gras R., Briand H., Peter P. (1996) Structuration sets with implication intensity", Proceedings of the International Conference on Ordinal and Symbolic Data Analysis - OSDA 95, E.Diday, Y.Chevallier, Otto Opitz, Eds., Springer, Paris, 147-156.
\bibitem{Grash} Gras R., Briand H., Peter P., Philippé J. (1997) Implicative statistical analysis, Proceedings of International Congress I.F.C.S., 96, Kobé, Springer-Verlag, Tokyo , 1997, 412-419