1. Sets, Lattices and Boolean Algebras;Abbott,1976
2. Social Choice and Individual Values;Arrow,1963
3. Medians in median graphs;Bandelt;Discr. Appl. Math.,1984
4. Median algebras;Bandelt;Discr. Math.,1983
5. Medianes, Condorcet et Kendall;Barbut;Note SEMA,1967