First-ever discovery of a superoutburst in GP Comae Berenices buried in archival data. - Kojiguchi, Naoto; Isogai, Keisuke; Tampo, Yusuke; Kato, Taichi; Ohnishi, Ryuhei; Imada, Akira; Nogami, Daisaku (Publications of the Astronomical Society of Japan, 2025)