The regions of Serbia include geographical and, to a lesser extent, traditional and historical areas. Geographical regions have no official status, though some of them serve as a basis for the second-level administrative divisions of Serbia, okrugs. Not being administratively defined, the boundaries of the regions are in many cases vague: they may overlap, and various geographers and publications may delineate them differently, not just in the sense of regions' extents, but also in the sense as to whether they form separate geographical entities or subsist as parts of other super-regions, etc.