Natsuhiko OTSUKA, Xiaoyang LI and Koh IZUMIYAMA(2018). The Northern Sea Route, recent activities and trend, Proc., 33rd Intl. Symp. on Okhotsk Sea and Polar Oceans, pp.**-**
Natsuhiko OTSUKA, Xiaoyang LI and Koh IZUMIYAMA(2018). The Northern Sea Route, recent activities and trend, Proc., 33rd Intl. Symp. on Okhotsk Sea and Polar Oceans, pp.**-**