Columbia subject headings:
Aerospace engineering--Congresses.
Astronautics--Congresses.
Space vehicles--Propulsion systems--Congresses.
Harvard subject headings:
Aerospace engineering--Congresses.
Astronautics--Congresses
Space vehicles--Propulsion systems--Congresses
Princeton subject headings:
Aerospace engineering--Congresses.
Astronautics--Congresses.
Space vehicles--Propulsion systems--Congresses.