Columbia subject headings:
Spectrum, Solar--Observations--Periodicals.
Sun--Faculae--Observations--Periodicals.
Sun--Observations--Periodicals.
Harvard subject headings:
Spectrum, Solar--Observations--Periodicals.
Sun--Faculae--Observations--Periodicals.
Sun--Observations--Periodicals.
Princeton subject headings:
Spectrum, Solar--Observations.
Sun--Faculae--Observations.
Sun--Observations.