Columbia subject headings:
Harvard subject headings:
Germany (East). Ministerium für Staatssicherheit--Correspondence.
Spies--Germany (East)--Correspondence.
Wolf, Markus, 1923-2006--Correspondence.
Princeton subject headings:
Germany (East). Ministerium für Staatssicherheit--Correspondence.
Spies--Germany (East)--Correspondence.
Wolf, Markus, 1923-2006--Correspondence.