Isotopic composition of gas hydrates in subsurface sediments from offshore Sakhalin Island, Sea of Okhotsk - Hachikubo, Akihiro; Krylov, Alexey; Sakagami, Hirotoshi; Minami, Hirotsugu; Nunokawa, Yutaka; Shoji, Hitoshi; Matveeva, Tatiana; Jin, Young K.; Obzhirov, Anatoly (Geo-Marine Letters, 2009)