1. Daniel,M.: Dempster's Semigroup and Uncertainty Processing in Rule Based Expert Systems. Ph.D. thesis, Academy of Sciences of the Czech Republic, Prague, 1993, (in Czech).
2. Dempster,A.P.: A generalization of Bayesian inference. J. of Roy. Stat. Soc. Ser. B, 30, 1968, 205.
3. Dubois,D.: Belief structures, possibility theory and decomposable confidence measures. Computers and AI, 5, 1986, 403–416.
4. Esteva,F., Garcia-Calvés,P., Godo,L.: Enriched Interval Bilattices and Partial Many-Valued Logics: An Approach to Deal with Graded Truth and Imprecision. In: International Journal of Uncertainty, Fuzziness and Knowledge-based Systems, World Scientific, Vol.2, No.1, 1994, pp.37–54.
5. Fuchs,L.: Partially ordered algebraic systems. Pergamon Press, 1963.