Greif, M. 200 challenging chess puzzles. Goodwill Publishing House.
Chicago Style (17th ed.) CitationGreif, Martin. 200 Challenging Chess Puzzles. New Delhi: Goodwill Publishing House.
MLA (9th ed.) CitationGreif, Martin. 200 Challenging Chess Puzzles. Goodwill Publishing House.
Warning: These citations may not always be 100% accurate.