A Preliminary Study of the Number of Votes under Majority Rule in Crowdsourcing. - Yuki Okubo; Teruaki Kitasuka; Masayoshi Aritsugi (KES, 2013)

Forbidden quadruplets generating a finite set of 2-connected graphs. - Michitaka Furuya; Yuki Okubo (Discret. Math., 2015)