Notes of welcome. - Claude Berge; Paul Erdös; Sin Hitotumatu; Loo Keng Hua; Richard Rado (Graphs Comb., 1985)

The Euler Line after All: 11272. - Vasile Mihai; Sin Hitotumatu (Am. Math. Mon., 2008)

A recursive Algorithm for the k-face Numbers of Wythoffian-n-polytopes Constructed from Regular Polytopes. - Jin Akiyama; Sin Hitotumatu; Motonaga Ishii; Akihiro Matsuura; Ikuro Sato; Shun Toyoshima (J. Inf. Process., 2017)