The map shows the initial positions of the Axis forces and the Yugoslav Royal Army.
Own work
This file was derived from:

 Yugoslavia (1939–41) location map.svg
Flag of Germany (1935–1945).svg
Flag of Italy (1861-1946) crowned.svg
Flag of Hungary (1915-1918, 1919-1946).svg
APP-6 Mountain Infantry.svg
NATO Map Symbol - Motorised Infantry.svg
Flag of Yugoslavia (1918–1941).svg
State Flag of Greece (1863-1924 and 1935-1973).svg
Flag of the United Kingdom.svg
BlankMap-World gray.svgDerived from;

Maps for free
OSMInformation from:

Vojna enciklopedija, editor Nikola Gažević, pages 186-187.
Kaštel Stari
Goran tek-en, following request by and knowledge from Kaštel Stari