Columbia subject headings:
Harvard subject headings:
Professions--Europe--Congresses.
Professions--Germany--Congresses.
Self-employed--Europe--Congresses.
Self-employed--Germany--Congresses.
Universität Lüneburg. Forschungsinstitut Freie Berufe--Congresses.
Princeton subject headings:
Professions--Europe--Congresses.
Professions--Germany--Congresses.
Self-employed--Europe--Congresses.
Self-employed--Germany--Congresses.
Universität Lüneburg. Forschungsinstitut Freie Berufe--Congresses.