Papers
H. Shibahara, A C^m Whtiney Extension Theorem for Horizontal Curves in Free Step 2 Carnot Groups, Preprint.
S. Rogovin, H. Shibahara, Q. Zhou, Some remarks on the Gehring-Hayman theorem, Annales Fennici Mathematici, 48(1), 141-152.
H. Shibahara, Gromov-Hasdorff distance with boundary, Preprint.