Analysis of information sources in references of the Wikipedia article "Ελληνο-Γιουγκοσλαβική συνομοσπονδία" in Greek language version.
Only two countries, Yugoslavia and Greece, were in the Allied camp, which explains why practical plans of a regional Balkan confederation had to be restricted to them.
Negotiations lasting until the end of 1941 led to the conclusion of an agreement, signed on January 15, 1942, by Prime Ministers Tsouderos and Slobodan Jovanovid, concerning the establishment of a Balkan Union whose primary