Columbia subject headings:
Interstellar communication--Congresses.
Life on other planets--Congresses.
Life--Origin--Congresses.
Harvard subject headings:
Interstellar communication--Congresses.
Life on other planets--Congresses
Life--Origin--Congresses
Princeton subject headings:
Interstellar communication--Congresses.
Life on other planets--Congresses.
Life--Origin--Congresses.