1. Ordre et classification;Barbut,1970
2. Lattice Theory;Birkhoff,1940
3. Orderings of Coxeter groups;Björner,1984
4. Generalized quotients in Coxeter groups;Björner;Trans. Amer. Math. Soc.,1988
5. Groupes et Algèbres de Lie, Chapitres 4, 5, 6;Bourbaki,1968