Semantics of Logic

Assigning Meaning to Proofs - Report by Robert Constable, subtitled `A semantic basis for problem solving environments'. Constable's aim is to use metamathematical results to guide the making of framewroks for constructive logic, as part of the NuPrl project.
http://www.cs.cornell.edu/Info/Projects/NuPrl/documents/semantics/it.html

Satisfaction - An introduction to the model-theoretic stasfaction relation, by Peter Suber.
http://www.earlham.edu/~peters/courses/logsys/satisfac.htm

On the Meaning of the Logical Constants and the Justifications of the Logical Laws - Lecture notes of Per Martin-Löf. Argues that a close analysis of the concepts of proof, judgement and justification yield a direct, constructive account of the meaning of logical judgements.
http://www.hf.uio.no/filosofi/njpl/vol1no1/meaning/meaning.html

What Can't Be Evaluated, Can't Be Evaluated; and It Can't Be Supervalued Either - Essay by Jerry Fodor and Ernie Lepore attacking an argument for maintaining principle of the excluded middle in the absence of bivalence by the device of supervaluations.
http://ruccs.rutgers.edu/tech_rpt/evaluate19.pdf

Interpreting Formal Logic - Article by Jaroslav Peregrin.
http://jarda.peregrin.cz/mybibl/PDFTxt/309.pdf

Torkel Franzén's Homepage - Contains his PhD thesis, `Provability and Truth'.
http://www.sm.luth.se/~torkel/

The Meanings of Logical Constants - Essay by Gilbert Harman, arguing for Prawitz's approach to the semantics of logic based upon a conceptual role semantics.
http://www.nyu.edu/gsas/dept/philo/courses/concepts/meaning.html