Columbia subject headings:
Harvard subject headings:
Gutenberg-Gymnasium Erfurt (Erfurt, Germany)--Congresses.
Mass media--Social aspects--Germany--Erfurt--Congresses.
School shootings--Germany--Erfurt--Congresses.
School violence--Germany--Erfurt--Congresses.
Warnings--Congresses.
Princeton subject headings:
Gutenberg-Gymnasium Erfurt (Erfurt, Germany)
School shootings--Germany--Erfurt.
School violence--Germany--Erfurt.
Warnings.