What are some good sources to learn about historical warfare?

I've noticed that a lot of fantasy does borrow elements from historical battles and wars, but I'm fairly certain those instances are often paired with a degree of creative twisting and freedom-taking.<br><br>If I want to go straight to the source, what are some recommended works to learn about historical warfare?<br>I'm interested in everything from the classical greco-roman era to World War II. What are some good texts to read?<br><br>For context, I've already had a course in the history of war (WWI and WWII, and from classical to medieval) in my first year of university, but I want to go more in depth and get more sources than just that one book.