Overlay image for Croatia location map, indicating three sets of territories distinguished within the Z-4 Plan: green - autonomous regions, purple - 5-year transition period, red - transfer to Croatian control without any transitional period
Ahrens, Geert-Hinrich (2007). Diplomacy on the Edge: Containment of Ethnic Conflict and the Minorities Working Group of the Conferences on Yugoslavia. Washington, D.C.: Woodrow Wilson Center Press. ISBN 978-0-8018-8557-0., pp. 158-159, 182; Naselja i stanovništvo RH od 1857-2001. godine (in Croatian). Croatian Bureau of Statistics
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