Columbia subject headings:
Harvard subject headings:
Ōnishi, Hajime, 1864-1900--Correspondence.
Philosophers--Japan--Correspondence.
Ōnishi, Ikuko, 1870-1945.
Princeton subject headings:
Ōnishi, Hajime, 1864-1900--Correspondence.
Ōnishi, Ikuko, 1870-1945.
Philosophers--Japan--Correspondence.