Columbia subject headings:
Astrometry--Congresses.
Galaxies--Congresses.
Pulsating stars--Congresses.
Harvard subject headings:
Astrometry--Congresses
Galaxies--Congresses
Pulsating stars--Congresses.
Princeton subject headings:
Astrometry--Congresses.
Galaxies--Congresses.
Pulsating stars--Congresses.