Columbia subject headings:
Harvard subject headings:
Crowd control--Germany--Congresses.
Crowdsourcing--Germany--Congresses.
Economics--Germany--Sociological aspects--Congresses.
Flextime--Germany--Congresses.
Self-employed--Germany--Congresses.
Princeton subject headings:
Crowd control--Germany--Congresses.
Crowdsourcing--Germany--Congresses.
Economics--Germany--Sociological aspects--Congresses.
Flextime--Germany--Congresses.
Self-employed--Germany--Congresses.