Columbia subject headings:
Authors, German--20th century--Biography--Congresses.
Becher, Johannes Robert, 1891-1958--Congresses.
Harvard subject headings:
Authors, German--20th century--Biography--Congresses.
Becher, Johannes Robert, 1891-1958--Congresses.
Princeton subject headings:
Becher, Johannes Robert, 1891-1958--Congresses.