: Isolated queen pawn (168 positions), hedgehog structures (108 positions), and Sicilian sacrifices (168 positions) .
: Comprehensive PGN databases of historic games mentioned in Polgár's works are often available for free download at PGN Mentor . Deep Training Structure (77 Themes) laszlo polgar chess middlegames pgn verified
: Specific chapters dedicated to sacrifices on : Isolated queen pawn (168 positions), hedgehog structures