| 1991 | A Brief Overview of Possibilistic Logic. Didier Dubois, Jérôme Lang, Henri Prade |
| 1991 | A Constraint-Based Approach to Uncertain and Imprecise Reasoning. Application to Expert Systems. T. Pontet |
| 1991 | A Hybrid Approach for Modeling Uncertainty in Terminological Logics. Jochen Heinsohn |
| 1991 | A Logic of Imprecise Monadic Predicades and its Relation to the S5-Modal Fuzzy Logic. Akira Nakamura |
| 1991 | A Modal Analysis of Possibility Theory. Luis Fariñas del Cerro, Andreas Herzig |
| 1991 | A New Approach to Inference Under Uncertainty for Knowledge Based Systems. James F. Baldwin |
| 1991 | A Preferential Model Semantics For Default Logic. Frans Voorbraak |
| 1991 | A Tableau-Based Characterisation for Default Logic. Camilla Schwind, Vincent Risch |
| 1991 | Abduction in Labelled Deductive Systems - A Conceptual Abstract. Dov M. Gabbay |
| 1991 | Advance Prototyping. Simon Parsons |
| 1991 | An Entity-Relationship Approach to Modelling of Vagueness in Databases. R. Vandenberghe, Rita M. M. De Caluwe |
| 1991 | An Evidential Reasoning Approach to the Classification of Satellite Images. Gabriele Lohmann |
| 1991 | An Extended Logic Language For Representing Belief. John Fox, Paul J. Krause, Mirko Dohnal |
| 1991 | An Extension of the Possibility Theory in View of the Formalization of Approximate Reasoning. L. Gacôgne |
| 1991 | Assertional Default Theories. Gerhard Brewka |
| 1991 | Assessment of Qualitative Judgements for Conditional Events in Expert Systems. Giulianella Coletti, Angelo Gilio, Romano Scozzafava |
| 1991 | Automated Reasoning About an Uncertain Domain. Flávio S. Corrêa da Silva, David Stuart Robertson, Paul W. H. Chung |
| 1991 | Computing Extensions of Default Theories. François Lévy |
| 1991 | Default Logics. Philippe Besnard |
| 1991 | Difference Fuzzy Relation Equations: Studies in Dynamical Systems. Antonio Di Nola, Witold Pedrycz, Salvatore Sessa |
| 1991 | Efficient Algorithms for Belief Functions based on the Relationship netween Belief and Probability. Michael Clarke, Nic Wilson |
| 1991 | Elementary Hyperentailment -Nonmonotonic reasoning about defaults-. Emil Weydert |
| 1991 | Every Complex System can be Determined by a Causal Probabilistic Network Without Cycles and Every Such Network Determines a Markov Field. Ulrich G. Oppel |
| 1991 | Formalizing Pertinence Links in Inheritance Reasoning: Preliminary Report. Éric Grégoire |
| 1991 | From Data Analysis to Uncertainty Knowledge Analysis. Edwin Diday |
| 1991 | Fuzzy Control Research at Siemens Corporate R&D. Hans Hellendoorn, Michael Reinfrank |
| 1991 | Graded Default Logics. Christine Froidevaux, Philippe Chatalic, Jérôme Mengin |
| 1991 | Handling Active Databases with Partial Inconsistencies. Opher Etzion |
| 1991 | Handling Partially Ordered Defaults in TMS. Ulrich Junker, Gerhard Brewka |
| 1991 | Handling Uncertainty in Knowledge-Based Computer Vision. Luis Enrique Sucar, Duncan Fyfe Gillies |
| 1991 | Hierarchical Default Logic. Craig MacNish |
| 1991 | Imprecise Quantifiers and Conditional Probabilities. Stéphane Amarger, Didier Dubois, Henri Prade |
| 1991 | Induction of Uncertain Rules and the Sociopathicity Property in Dempster-Shafer Theory. Yong Ma, David C. Wilkins |
| 1991 | Knowledge Extraction in Trivalued Propositional Logic. Antoine Rauzy |
| 1991 | Learning of Uncertain Classification Rules in Medical Diagnosis. Elisabetta Binaghi |
| 1991 | Learning with CASTLE. Silvia Acid, Luis M. de Campos, Antonio González, Rafael Molina, Nicolas Pérez de la Blanca |
| 1991 | Linguistically expressed uncertainty: its elicitation and use in modular expert systems. Lluís Godo, Ramón López de Mántaras |
| 1991 | Managing Uncertainty in Environmental Analysis: An Application to Measurement Data Interpretation. Marcus Spies |
| 1991 | Nonmonotonic inference, expectations, and neural networks. Peter Gärdenfors |
| 1991 | On Commitment and Cumulativity in Default Logics. Torsten Schaub |
| 1991 | On Truth and Utility. Enrique H. Ruspini |
| 1991 | Press - A Probabilistic Reasoning Expert System Shell. Zhiyuan Luo, Alex Gammerman |
| 1991 | Probabilistic Default Reasoning Involving Continous Variables. Gerhard Paass |
| 1991 | Probabilistic Reasoning With Facts And Rules In Deductive Databases. Helmut Thöne, Ulrich Güntzer, Werner Kießling |
| 1991 | Probabilistic Regions of Persistence. Scott D. Goodwin, Eric Neufeld, André Trudel |
| 1991 | Propagation of Uncertainty in Dependence Graphs. José E. Cano, Miguel Delgado, Serafín Moral |
| 1991 | Random Closed Sets: a Unified Approach to the Representation of Imprecision and Uncertainty. Philippe Quinio, Takashi Matsuyama |
| 1991 | Reasoning with Mass Distributions and the Context Model. Rudolf Kruse, Jörg Gebhardt, Frank Klawonn |
| 1991 | Restraining the Proliferation of Worlds in Probabilistic Logic Entailments. Paul Snow |
| 1991 | Revision in Propositional Calculus. Odile Papini |
| 1991 | Symbolic and Quantitative Approaches to Reasoning and Uncertainty, European Conference, ECSQAU, Marseille, France, October 15-17, 1991, Proceedings Rudolf Kruse, Pierre Siegel |
| 1991 | The Reliability of Reasoning with Unreliable Rules and Propositions. Luis Cardona, Jürg Kohlas, Paul-André Monney |
| 1991 | The Transferable Belief Model. Philippe Smets, Yen-Teh Hsia, Alessandro Saffiotti, Robert Kennes, Elizabeth Umkehrer |
| 1991 | Towards a Logic for a Fuzzy Logic Controller. Dimiter Driankov, Hans Hellendoorn |
| 1991 | Uncertainty in the valuation of risky assets. Alain Chateauneuf, Robert Kast, André Lapied |
| 1991 | Using Defeasible Logic for a Window on a Probabilistic Database: Some Preliminary Notes. James Cussens, Anthony Hunter |
| 1991 | Using Maximum Entropy to Identify Unsafe Assumptions in Probabilistic Expert Systems. Paul C. Rhodes, Gerald R. Garside |