DJVU PDF Siripen Ungsitipoonporn. 2008, "The Bangkok Hakka Phonology", in The Mon-Khmer Studies Journal, vol. 38, pp. 185-208. cite.

Siripen Ungsitipoonporn 2001, "A phonological comparison between Khlongphlu Chong and Wangkraphrae Chaong", Master thesis, Mahidol University. cite.