Columbia subject headings:
Einstein, Albert, 1879-1955--Anniversaries, etc.--Congresses.
Symmetry--Congresses.
Harvard subject headings:
Einstein, Albert, 1879-1955--Anniversaries, etc.--Congresses.
Symmetry--Congresses.
Princeton subject headings:
Einstein, Albert, 1879-1955--Anniversaries, etc.--Congresses.
Symmetry--Congresses.