Columbia subject headings:
Ionized gases--Congresses.
Peimbert, Manuel, 1941-
Planetary nebulae--Congresses.
Torres-Peimbert, Silvia.
Harvard subject headings:
Ionized gases--Congresses.
Peimbert, Manuel, 1941-
Planetary nebulae--Congresses.
Torres-Peimbert, Silvia.
Princeton subject headings:
Ionized gases--Congresses.
Planetary nebulae--Congresses.