Columbia subject headings:
Astronomy--Observations.
Calendar, Chinese.
China--History--To 221 B.C.
Chronology, Chinese.
Harvard subject headings:
Astronomy--Observations
Calendar, Chinese.
China--History--To 221 B.C.
Chronology, Chinese.
Princeton subject headings:
Astronomy--Observations.
Calendar, Chinese.
China--History--To 221 B.C.
Chronology, Chinese.