Marilyn A. Reba, "Puzzles, Paradoxes, and Problem Solving: An Introduction to Mathematical Thinking" English | ISBN: 1482227533 | 2015 | 605 pages | PDF | 5 MB
Across the Board: The Mathematics of Chessboard Problems by John J. Watkins 2004 | ISBN: 0691115036, 0691130620, 0691154988 | English | 272 pages | True PDF | 7 MB