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Ernest Hemingway - "For Whom the Bell Tolls"
Che Guevara - "Episodes of the Revolutionary War"
Gabriel Garcia Marquez - "One Hundred Years of Solitude", "No One Writes to the Colonel"
These are the most important ones. There are many more related to his field of study... I suggest creating a separate thread about Lev Gumilev.
I used to love adventure stories... "Treasure Island", "The Tale of Manco the Bold". And I still adore Jack London!