1. Statistical Reasoning with Imprecise Probabilities;Walley,1991
2. L.A. Zadeh, Test-score semantics for natural languages and meaning representation via PRUF, in: B. Rieger (Ed.), Empirical Semantics, Brockmeyer, Bochum, W. Germany, 1982, pp. 281–349. Also Technical Memorandum 246, AI Center, SRI International, Menlo Park, CA., 1981.
3. Toward a perception-based theory of probabilistic reasoning with imprecise probabilities;Zadeh;J. Statist. Plann. Inference,2002
4. Precisiated natural language (PNL);Zadeh;AI Magazine,2004