Mahboob & Ahmar (2004),第1009頁. Mahboob, Ahmar; Ahmar, Nadra H., Pakistani English: phonology, Schneider, Edgar W. (编), A handbook of varieties of English 1, Berlin; New York: Mouton de Gruyter: 1003–1015, 2004 [2022-07-02], (原始内容存档于2021-11-16)
Harrington, Cox & Evans (1997). Harrington, J.; Cox, F.; Evans, Z., An acoustic phonetic study of broad, general, and cultivated Australian English vowels, Australian Journal of Linguistics, 1997, 17 (2): 155–84, doi:10.1080/07268609708599550
Roach (2004),第242頁. Roach, Peter, British English: Received Pronunciation, Journal of the International Phonetic Association, 2004, 34 (2): 239–245, doi:10.1017/S0025100304001768
Verhoeven (2007),第221頁. Verhoeven, Jo, The Belgian Limburg dialect of Hamont, Journal of the International Phonetic Association, 2007, 37 (2): 219–225, doi:10.1017/S0025100307002940
Mahboob & Ahmar (2004),第1009頁. Mahboob, Ahmar; Ahmar, Nadra H., Pakistani English: phonology, Schneider, Edgar W. (编), A handbook of varieties of English 1, Berlin; New York: Mouton de Gruyter: 1003–1015, 2004 [2022-07-02], (原始内容存档于2021-11-16)