Sakihara, Mitsugu; Curry, Stewart; Serafim, Leon Angelo (2006). Okinawan-English Wordbook: A Short Lexicon of the Okinawan Language with English Definitions and Japanese Cognates. University of Hawaii Press. ISBN9780824831028
Serafim, Leon A (2008). “The uses of Ryukyuan in understanding Japanese language history”. In Frellesvig, Bjarke; Whitman, John. Proto-Japanese: Issues and Prospects. John Benjamins. pp. 79-99. ISBN9789027248442
Shinzato, Rumiko; Serafim, Leon Angelo (2013). Synchrony and diachrony of Okinawan Kakari Musubi in comparative perspective with premodern Japanese. Brill. ISBN9789004219021