Columbia subject headings:
Harvard subject headings:
Civil defense--Germany (East)--Chronology.
Germany (East)--Armed Forces--Chronology.
Germany (East)--History, Military--Chronology.
Germany (East). Nationale Volksarmee--History--Chronology.
Princeton subject headings:
Germany (East)--History, Militrary--Chronology.
Germany (East). Grenztruppen der DDR--History--Chronology.
Germany (East). Nationale Volksarmee--History--Chronology.
Zivilverteidigung der DDR--History--Chronology.