CalcuDoku, 101 Advanced Puzzles
Note: a 4th edition of this book is available now, with 20 brand new puzzles added:<br /><br />amazon.com/Calcudoku-121-Advanced-Puzzles/dp/1536973068<br /><br />(this 3rd edition will go out of print soon)
CalcuDoku 9x9 - Hard - Volume 10 - 276 Puzzles
Calcudoku: 121 Advanced Puzzles (Advanced Calcudoku Puzzles) (Volume 2)
KenKen: For Experts Only: 100 Challenging Logic Puzzles That Make You Smarter
Kendoku: Extreme: 150 Brutal Puzzles to Build Your Brain
Kendoku: Volume 2: The Next Logical Step
Will Shortz Presents The Dangerous Book of KenKen: 100 Very Hard Logic Puzzles That Make You Smarter
CalcuDoku Mixed Grids - Easy to Hard - Volume 1 - 276 Puzzles
Black Belt KenKenĀ® (Martial Arts Puzzles Series)