Scholarship

• Dynamic epistemic logics
• Logic programming
• Modal logics

Educational materials

• Average Seek Time of a Computer Disk
• Prolog and Lisp code

Resources

General

• Wikipedia
• Scholarpedia
  
• Internet Archive - Texts
  
• Google Scholar
• English Word Information
• SpringerLink

Mathematics

• Proof wiki
• Encyclopedia of Mathematics
• MathWorld
• Planet Math Encyclopedia
  
• JSTOR mathematics journals
• AMS Notices and Bulletin
• Cut the Knot
  

Logic

• Synthese
• Journal of Symbolic Logic
• Bulletin of Symbolic Logic
• Studia Logica
• Bulletin of the Section of Logic
  
• TARK -- Theoretical Aspects of Reasoning about Knowledge
• Journal of Logic and Computation (subscription required)
  

Philosophy

• Stanford Encyclopedia of Philosophy
• Internet Encyclopedia of Philosophy
• Journal of Philosophy of Science
• The British journal for the Philosophy of Science
• Mind