Both Worldatlas and Wikipedia disagree with you and include Serbia in Southern Europe
https://www.worldatlas.com/articles/which-countries-make-up-... https://en.wikipedia.org/wiki/Southern_Europe
https://www.worldatlas.com/articles/which-countries-make-up-... https://en.wikipedia.org/wiki/Southern_Europe
[1] https://en.wikipedia.org/wiki/Regions_of_Europe [2] https://en.wikipedia.org/wiki/Serbia
EDIT: It's like saying that Arizona is part of the Southern United States.