1. AUBIN, J.P. (1994): Initiation á l’analyse appliquäe, Masson.
2. BOCK H.H. (2001): Clustering algorithms and Kohonen maps for symbolic data. Proc. ICNCB, Osaka, 203–215.
3. BOCK H.H. and DIDAY, E. (eds.) (2000): Analysis of symbolic data. Exploratory methods for extracting statistical information from complex data. Springer Verlag, Heidelberg.
4. DE CARVALHO, F.A.T. (1998): Extension based proximities coefficients between boolean symbolic objects. In: C. Hayashi et al. (eds): Data Science, Classification and Related Methods, Springer Verlag, 370–378.
5. DE CARVALHO, F.A.T, DE SOUZA, R.M., VERDE, R. (2001): Symbolic classifier based on modal symbolic descriptions. Proc. CLADAG2001, Univ. de Palermo.