You could go back even further and show that Serbia was once established on the territory of Bosnia and had control of 50% of the Dalmatian coast.
The point is that the national borders that we see today emerging from ex-Yugoslavia are those that Tito drew up in 1943.
(I note that my own view is that Tito shouldn't have re-instated national borders, and should have taken over the pre-1939 centralisation policy while stripping it of the Serb-first element, and adding more cultural autonomy.) *Lunatic*, n. One whose delusions are out of fashion.
The map of the Banovinas that I posted represents the boundaries set up in 1929 which were effective up until 1939.
The borders established by the Cvetković-Maček Agreement were only effective as of 1939 for 2 years, up until the creation of Nazi puppet state NDH. NDH occupied what is today's Croatian plus Bosnian territories. IMHO, there is no basis to say that these frontiers (as opposed to others) should be used to compare the situations pre and post WWII.
In fact, all of these borders were of administrative nature and have no relation with the ethnic composition of the territories. If national self-determination is the goal, then maps based on ethnic composition of the population are most appropriate.
Which Serbia and era? *Lunatic*, n. One whose delusions are out of fashion.