<a href="https://en.wikipedia.org/wiki/Okano_Keijir%C5%8D" class="extiw" title="en:Okano Keijirō">Keijirō Okano</a>
Unknown author<span style="display: none;">Unknown author</span>
1921
<i>Shōhō Ronbun Sen</i>, Vol. 1, <i>Okano Kyōju Zaishoku Nijūgonen Shukugakai</i>, 1921.