Splitting theorems for nonnegatively curved open manifolds with large ideal boundary. Takashi Shioya — 1993 Mathematische Zeitschrift
Mass of rays in Alexandrov spaces of nonnegative curvature. Takashi Shioya — 1994 Commentarii mathematici Helvetici
Parabolic isometries of CAT(0) spaces and CAT(0) dimensions. Fujiwara, Koji; Shioya, Takashi; Yamagata, Saeko — 2004 Algebraic & Geometric Topology