Facial achromatic number of triangulations on the sphere. - Naoki Matsumoto; Yumiko Ohno (Discret. Math., 2020)

Achromatic number and facial achromatic number of connected locally-connected graphs. - Naoki Matsumoto; Yumiko Ohno (Discret. Appl. Math., 2021)

The existence of uniform hypergraphs for which the interpolation property of complete coloring fails. - Nastaran Haghparast; Morteza Hasanvand; Yumiko Ohno (Discret. Math., 2022)

Note on fair game edge-connectivity of graphs. - Michitaka Furuya; Naoki Matsumoto; Yumiko Ohno; Kenta Ozeki (Discret. Appl. Math., 2023)