Columbia subject headings:
Harvard subject headings:
Listening (Philosophy)--Congresses.
Sound--Psychological aspects--Congresses.
Voice (Philosophy)--Congresses.
Voice culture--Congresses.
Voice--Psychological aspects--Congresses.
Princeton subject headings:
Listening (Philosophy)--Congresses.
Sound--Psychological aspects--Congresses.
Voice (Philosophy)--Congresses.
Voice culture--Congresses.
Voice--Psychological aspects--Congresses.