Columbia subject headings:
I︠U︡on, Konstantin Fedorovich, 1875-1958.
Harvard subject headings:
I︠U︡on, Konstantin Fedorovich, 1875-
I︠U︡on, Konstantin Fedorovich, 1875-1958
Princeton subject headings:
I︠U︡on, Konstantin Fedorovich, 1875-1958.