Matsuda, Mitsugu (2001) The Government of the Kingdom of Ryukyu, 1609-1872: a dissertation submitted to the Graduate School of the University of Hawaii in partial fulfillment of the requirements for the degree of Doctor of Philosophy, January 1967, Gushikawa: Yui Pub., 283 p., ISBN 4-946539-16-6
Smits, Gregory (1999) Visions of Ryukyu: identity and ideology in early-modern thought and politics, Honolulu: University of Hawai'i Press, 213 p., ISBN 0-8248-2037-1
↑ Takara Kurayoshi (1996). The Kingdom of Ryukyu and Its Overseas Trade; Sources of Ryukyuan History and Culture in European Collections. , J. Kreiner Ed., Munchen. tr. 46. ISBN978-3-89129-493-2.
