Quick answer — Masami Okui worked on Horizon in the Middle of Nowhere II (Theme Song Performance), Di Gi Charat (Theme Song Performance), Please Put Them On, Takamine-san (Theme Song Performance).
Masami Okui worked on Horizon in the Middle of Nowhere II (Theme Song Performance), Di Gi Charat (Theme Song Performance), Please Put Them On, Takamine-san (Theme Song Performance).
