1. A. Arnault and P. Nicole,La Logique ou l'Art de Penser (Flammarion, Paris, 1662, 1970).
2. M. Barbut and B. Monjardet,Ordre et Classification, Algèbre et Combinatoire, Vols. 1 and 2 (Hachette, Paris, 1970).
3. P. Bertrand, Etude de la représentation pyramidale, Thèse de 3ème cycle, Univ. Paris-IX Dauphine (1986).
4. P. Bertrand and E. Diday, A visual representation of the compatibility between an order and a dissimilarity index: the pyramids, in: Comp. Statist. Quarterly 2 (1985) 31–42.
5. G. Birkhoff,Lattice Theory, American Mathematical Society Colloquium Publications, Vol. 25, 3rd ed. (1967).