Columbia subject headings:
Bulgarian language--Etymology--Names.
Montana (Bulgaria : Oblast)--History, Local.
Names, Geographical--Bulgaria--Montana (Oblast)
Harvard subject headings:
Bulgarian language--Etymology--Names.
Mikhaĭlovgradska oblast (Bulgaria)--History, Local.
Mikhaĭlovgradski okrŭg (Bulgaria)--History, Local.
Names, Geographical--Bulgaria--Mikhaĭlovgradski okrŭg.
Princeton subject headings: