Proof Theory

The Calculus of Structures - The calculus of structures is a new proof theoretical formalism. It exploits a top-down symmetry of derivations made possible by deep inference.
alessio.guglielmi.name/res/cos/index.html

The Epsilon Calculus - Discussion of David Hilbert's development of this type of logical formalism with emphasis on proof-theoretic methods.
plato.stanford.edu/entries/epsilon-calculus/

G. Japaridze's Papers - Full list of publications by this author, with about 30 items in the area of proof theory. Many of the papers are downloadable.
www.csc.villanova.edu/~japaridz/study.html

Linear Network - Linear Logic in Computer Science is lead by the "Logic of Programming" research team. Its thematic is focused on developing the theory and the applications of Linear Logic. It is formed by seven sites located in Marseille, Bologna, Cambridge, Edinburgh, Lisboa, Paris and Roma, and a few subsites.
iml.univ-mrs.fr/ldp/LINEAR/

Logic of programming - The "Logic of Programming" research team is interested in proof theory and its relations with theoretical computer science. The main topic is mathematical interpretation of proofs : nets (proof = graph), denotational semantics (proof = function), and game semantics (proof = strategy). Two realisations of this working programm are Linear Logic and Ludics.
iml.univ-mrs.fr/ldp/welcome.html

Mathematical Reasoning Group - Research group based in Edinburgh, it is running on the interaction between logic, mathematics and informatics. Links to publications, homepages, reports.
dream.dai.ed.ac.uk/

Proof Theory - Open Encyclopedia entry. Hierarchically organized by subtopics.
open-site.org/Science/Mathematics/Logic/Proof_Theory/

Proof Theory as an Alternative to Model Theory - Short article by Dale Miller, arguing that logic programming languages should base their semantics on proof theory, not model theory.
www.lix.polytechnique.fr/Labo/Dale.Miller/papers/ProofTheoryAsAlternative.html

ProofTheory.ORG - Basic material on proof theory and the home page of the only mailing list devoted to proof theory, with hundreds of experts.
www.prooftheory.org/