Title: Puzzle-based Learning: Introduction to critical thinking, mathematics, and problem solving, Author: Z Michalewicz
Title: Amusements in Mathematics, Author: Henry Ernest Dudeney
Title: Train Your Brain: A Year's Worth of Puzzles / Edition 1, Author: George Gratzer
Title: Mrs. Perkins's Electric Quilt: And Other Intriguing Stories of Mathematical Physics, Author: Paul Nahin
Title: Twenty More Problem Solving Skills For Mathcounts Competitions, Author: Jane Chen