World War II boots ?

Dear friends, these are the boots that I got from a friend of mine from Serbia
I do not know much about them, my friend, it is aimed at the small town of Krusevac in Serbia, he told me that the boots used "Chetniks" in World War II.

I'd like to know which army they belonged boots, if you have any information I would like to share it with me.

Thanks in advance!