1. Caspard, N., Leclerc, B., Monjardet, B.: Finite Ordered Sets: Concepts, Results and Uses. Springer, New York (2007)
2. Habib, M.: Comparability invariants. Ann. Discrete Math. 23, 371–386 (1984)
3. Kelly, D.: Invariants of finite comparability graphs. Order 3, 155–158 (1986)
4. Kong, T.Y., Ribemboim, P.: Chaining of Partially Ordered Sets. C. R. Acad. Sci. Paris, t. 319, Série I 533–537 (1994)
5. Sadi, B.: Suite d’Ensembles Partiellement Ordonnés. Arima 4, 66–71 (2006)