Columbia subject headings:
Astronomy--Study and teaching--Congresses.
Galaxies--Observations--Congresses.
Science--Study and teaching--Congresses.
Harvard subject headings:
Astronomy--Study and teaching--Congresses.
Galaxies--Observations--Congresses.
Science--Study and teaching--Congresses
Princeton subject headings:
Astronomy--Study and teaching--Congresses.
Galaxies--Observations--Congresses.
Science--Study and teaching--Congresses.