Invited Papers -- Nonmonotonic Reasoning in FLORA-2 -- Data Integration and Answer Set Programming -- Halo I: A Controlled Experiment for Large Scale Knowledge Base Development -- ASP Foundations -- Unfounded Sets for Disjunctive Logic Programs with Arbitrary Aggregates -- Loops: Relevant or Redundant? -- Approximating Answer Sets of Unitary Lifschitz-Woo Programs -- On Modular Translations and Strong Equivalence -- ASP Extensions -- Guarded Open Answer Set Programming -- External Sources of Computation for Answer Set Solvers -- Answer Sets for Propositional Theories -- Applications -- An ID-Logic Formalization of the Composition of Autonomous Databases -- On the Local Closed-World Assumption of Data-Sources -- Computing Dialectical Trees Efficiently in Possibilistic Defeasible Logic Programming -- Actions and Causations -- An Approximation of Action Theories of and Its Application to Conformant Planning -- Game-Theoretic Reasoning About Actions in Nonmonotonic Causal Theories -- Some Logical Properties of Nonmonotonic Causal Theories -- odular-?: An Elaboration Tolerant Approach to the Ramification and Qualification Problems -- Algorithms and Computation -- Platypus: A Platform for Distributed Answer Set Solving -- Solving Hard ASP Programs Efficiently -- Mode-Directed Fixed Point Computation -- Lookahead in Smodels Compared to Local Consistencies in CSP -- Foundations -- Nested Epistemic Logic Programs -- An Algebraic Account of Modularity in ID-Logic -- Default Reasoning with Preference Within Only Knowing Logic -- Semantics -- A Social Semantics for Multi-agent Systems -- Revisiting the Semantics of Interval Probabilistic Logic Programs -- Routley Semantics for Answer Sets -- The Well Supported Semantics for Multidimensional Dynamic Logic Programs -- Application Track -- Application of Smodels in Quartet Based Phylogeny Construction -- Using Answer Set Programming for a Decision Support System -- Data Integration: a Challenging ASP Application -- Abduction and Preferences in Linguistics -- Inference of Gene Relations from Microarray Data by Abduction -- System Track -- nomore: A System for Computing Preferred Answer Sets -- Integrating an Answer Set Solver into Prolog: - -- circ2dlp — Translating Circumscription into Disjunctive Logic Programming -- Pbmodels — Software to Compute Stable Models by Pseudoboolean Solvers -- KMonitor– A Tool for Monitoring Plan Execution in Action Theories -- The nomore++ System -- Smodels A — A System for Computing Answer Sets of Logic Programs with Aggregates -- A DLP System with Object-Oriented Features -- Testing Strong Equivalence of Datalog Programs – Implementation and Examples -- SELP – A System for Studying Strong Equivalence Between Logic Programs -- cmodels – SAT-Based Disjunctive Answer Set Solver.