Related Clues:

• Piece of Internet address shortly providing logical system
• Brain, maybe supported by system of logic
• Set of principles - what the church musician must have if he's to play?
• Periodical's operating system for acquiring knowledge
• Boolean expression at heart of logic — one on which Aristotle wrote
• Perhaps brain working — there's a lot of logic to that
• Paper with no review of treatise written by Aristotle
• System of rules abused in Rangoon
• Instrument of thought
• Brain perhaps working -- there's logic to this