The Kienyang Dialect of Fukien (thesis). University of California, Berkeley. 1969. includes a description of the phonology of the Ding'an dialect.
Solnit, David B. (1982). «Linguistic Contact in Ancient South China: The Case of Hainan Chinese, Be, and Vietnamese». Proceedings of the Eighth Annual Meeting of the Berkeley Linguistics Society. 8: 219–230. doi:10.3765/bls.v8i0.2041.
«A synchronic phonology of Hainan dialect: Part I». Journal of Chinese Linguistics. 7 (1): 65–100. 1979a. JSTOR23753034. describes Wenchang dialect.
«A synchronic phonology of Hainan dialect: Part II». Journal of Chinese Linguistics. 7 (2): 268–302. 1979b. JSTOR23752923.