APA (7th ed.) Citation

Marx, G. (1980). The Groucho letters (Reprint.). Sphere Books.

Chicago Style (17th ed.) Citation

Marx, Groucho. The Groucho Letters. Reprint. London: Sphere Books, 1980.

MLA (9th ed.) Citation

Marx, Groucho. The Groucho Letters. Reprint. Sphere Books, 1980.

Warning: These citations may not always be 100% accurate.