Columbia subject headings:
A stars--Congresses.
N stars--Congresses.
Peculiar stars--Congresses.
Harvard subject headings:
A stars--Congresses.
N stars--Congresses.
Peculiar stars--Congresses.
Princeton subject headings:
A stars--Spectra--Congresses.
Stars--Atmospheres--Congresses.
Stars--Constitution--Congresses.