2.
Sudoku Toolbox : 500 Puzzles Each with a Sudoku-Toolbox Featuring 26 Puzzle-Techniques
by Peru, David
ISBN: 9781736452615
List Price: $11.95
3.
Taming the Sudoku Dragon 2nd Edition : A Comprehensive Beginner's Guide
by Peru, David
ISBN: 9781736452653
List Price: $11.95