Columbia subject headings:
Harvard subject headings:
Ch'oe, Ch'i-wŏn, 857-
Chʻoe, Chʻi-wŏn, 867---Philosophy.
Princeton subject headings:
Ch'oe, Ch'i-wŏn, 857---Knowledge--History.
Korea--History--To 935--Historiography.
Silla (Kingdom)--Historiography.