Serbia was a kindom in southeastern Europe. Following WWI Serbia united with Montenegro, Bosnia and Herzegovina, Croatia, Dalmatia and Slovenia to form the kindom of Yugoslavia. Some examples of Serbia stamps is as follows:
Or
NAPA
NOWTA
NOPTO MAPKA
(NOTOP MAPKA means "Postage due.")
SERBIEN
(Overprinted on stamps of Bosnia during Austrian occupation.)
SERBIEN
(Overprinted on stamps of Yugoslavia during German occupation.)
SERBIEN
(Overprinted on stamps of Yugoslavia during German occupation.)
