Collins, Beverley; Mees, Inger M., The Phonetics of Cardiff English, Coupland, Nikolas; Thomas, Alan Richard (编), English in Wales: Diversity, Conflict, and Change, Multilingual Matters Ltd.: 87–103, 1990, ISBN 1-85359-032-0使用|accessdate=需要含有|url= (帮助)
Eades, Domenyk; Hajek, John, Gayo, Journal of the International Phonetic Association, 2006, 36 (1): 107–115, doi:10.1017/S0025100306002416
Gordon, Matthew J., New York, Philadelphia, and other northern cities: phonology, Schneider, Edgar W.; Burridge, Kate; Kortmann, Bernd; Mesthrie, Rajend; Upton, Clive (编), A handbook of varieties of English, 1: Phonology, Mouton de Gruyter: 282–299, 2004, ISBN 3-11-017532-0
Lodge, Ken, A Critical Introduction to Phonetics, Continuum International Publishing Group, 2009, ISBN 978-0-8264-8873-2使用|accessdate=需要含有|url= (帮助)
Ternes, Elmer; Vladimirova-Buhtz, Tatjana, Bulgarian, Handbook of the International Phonetic Association, Cambridge University Press: 55–57, 1999, ISBN 0-521-63751-1
Urua, Eno-Abasi E., Ibibio, Journal of the International Phonetic Association, 2004, 34 (1): 105–109, doi:10.1017/S0025100304001550