European Resistance in the Second World War has a chapter on Yugoslavia, by Vjeran Pavlaković. Although I think the introductory background details about Yugoslavia pre-Second World War are a little too simplistic, the rest of the chapter is good.

There's also a chapter in that book regarding Greece, although I haven't read it, so I can't comment on how good that is.

If you want a book which goes into the Second World War in Bosnia specifically, I'd recommend Genocide and Resistance in Hitler’s Bosnia: The Partisans and the Chetniks 1941 - 1943, by Marko Attila Hoare. It's focused primarily on the conflicts within the resistance movements which sprung up against the Axis occupation, and how it was actually far more complicated than the often simple narrative of resistance fighter vs occupier. Lot's of changing sides, uneasy ceasefires, and various levels of collaboration.