Columbia subject headings:
Astronomers--Belgium--Biography--Congresses.
Big bang theory--Congresses.
Celestial mechanics--Congresses.
Cosmology--Congresses.
Lemaître, Georges, 1894-1966--Congresses.
Harvard subject headings:
Astronomers--Belgium--Biography--Congresses.
Big bang theory--Congresses.
Celestial mechanics--Congresses
Cosmology--Congresses.
Lemaître, Georges, 1894---Congresses.
Lemaître, Georges, 1894-1966--Congresses.
Princeton subject headings:
Astronomers--Belgium--Biography--Congresses.
Big bang theory--Congresses.
Celestial mechanics--Congresses.
Cosmology--Congresses.
Lemaître, Georges, 1894-1966--Congresses.