The frontier of the seas the problems of delimitation : proceedings of the 5th International Ocean Symposium = [Umi no kokky_o : "Umi no ky_okai kakutei o meguru mondai" : dai 5-kai Kokusai Kaiy_o Shimpoj_umu h_okokusho] : November 26-27, 1980. (Ocean Association of Japan, 1981)