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Submarine warfare - Wikipedia
Submarine Warfare in the Pacific in World War 2 - YouTube
List of submarines of World War II - Wikipedia
Submarine Warfare Played Major Role in World War II Victory
Allied submarines in the Pacific War - Wikipedia
Submarine in World War II - National Museum of American History
Submarines in World War II - U.S. National Park Service
Submarine Combat Patrols - NHHC
The Use—and Misuse—of Submarines in Great Power Combat
U-boat | German Submarine Warfare in WWI & WWII | Britannica