100 Headachingly Hard Mate in Two Chess Puzzles Composed by Sam Loyd: Improve Your Ability to Calculate Variations and Finding Checkmate : Justesen, Martin B.: Amazon.de: Bücher
Can You Solve The Hardest Puzzles On Chess.com? - Chess.com
Hard Chess Puzzle # 0073
Difficult puzzle. White to play, mate in 2. : r/chess
An Ancient Chess Puzzle That Engines CAN'T Solve! - Remote Chess Academy