100 Headachingly Hard Mate in Two Chess Puzzles Composed by Sam Loyd: Improve Your Ability to Calculate Variations and Finding Checkmate - Kindle edition by Justesen, Martin B.. Humor & Entertainment Kindle
Checkmate in Two Puzzles Test (Very Hard) - Chess.com
Hardest Mate in 2 puzzle - Chess Forums - Chess.com
Chess Tactics: Study 2 - Mate in 2 - TheChessWorld
Chess Tactics: Study 1 - Mate in 2 - TheChessWorld