Tsuji Kenji. Theories on Sources of International Law in the First period of 19th Century (2) -Natural law-. Saga University Economic Review. 1994. 27. 2. 1-21
Tsuji Kenji. The Qualified Neutrality-the leading theory of neutrality in the first period of 19th century-. Saga University Economic Review. 1993. 26. 2. 177-201