Columbia subject headings:
Wagner, Christian, 1835-1918--Criticism and interpretation--Congresses.
Wagner, Christian, 1835-1918--Influence--Congresses.
Harvard subject headings:
Wagner, Christian, 1835-1918--Criticism and interpretation--Congresses.
Wagner, Christian, 1835-1918--Influence--Congresses.
Princeton subject headings:
Wagner, Christian, 1835-1918--Criticism and interpretation--Congresses.
Wagner, Christian, 1835-1918--Influence--Congresses.