Natsuhiko OTSUKA, Hajime YAMAGUCHI, Kazutaka TATEYAMA and Takao KASHIWAGI(2018). Study on navigability of the Arctic Sea Route, Proc., 33rd Intl. Symp. on Okhotsk Sea and Polar Oceans, pp.**-**
Natsuhiko OTSUKA, Hajime YAMAGUCHI, Kazutaka TATEYAMA and Takao KASHIWAGI(2018). Study on navigability of the Arctic Sea Route, Proc., 33rd Intl. Symp. on Okhotsk Sea and Polar Oceans, pp.**-**