1. For detailed studies on the “Northern Territories” problem, see, for example, Kimie Hara, Japanese-Soviet/Russian Relations since 1945: A Difficult Peace (London and New York: Routledge, 1998);
2. Tsuyoshi Hasegawa, The Northern Territories Dispute and Russo-Japanese Relations, Vol. I, Between War and Peace, 1697–1985; Vol. II, Neither War nor Peace, 1985–1998 (Berkeley, CA: University of California Press, 1998);
3. Hiroshi Kimura, Nichiro Kokkyo Kosho-shi: Ryodo Mondai ni Ikani Torikumuka [A History of Japanese-Russian Border Negotiations] (Tokyo: Chuokoron-sha, 1993);
4. Takahiko Tanaka, Nisso Kokko Kaifuku no Shiteki Kenkyu [A Historical Study of the Japanese-Soviet Diplomatic Restoration] (Tokyo: Yuhikaku, 1993);
5. Haruki Wada, Hoppo Ryodo Mondai o Kangaeru [Considering the Northern Territories Problem] (Tokyo: Iwanami-shoten, 1990); Hoppo Ryodo Mondai—Rekishi to Mirai [Northern Territories—History and Future] (Tokyo: Asahi Shimbun-sha, 1999).