Logic - A Workbook: http://www.kpaprzycka.filozofia.uw.edu.pl/Publ/xLogicSelfTaught.html
Logic Riddles: http://bogglesworldesl.com/teaching_article2.htm
Logic Puzzle explanation: www.puzzles-on-line-niche.com/Kids-logic-puzzles-tutorial.html
Logic Puzzle explanation: www.puzzles-on-line-niche.com/Kids-logic-puzzles-tutorial.html
