Mahboob & Ahmar (2004), p. 1010. Mahboob, Ahmar; Ahmar, Nadra H. (2004), "Pakistani English: phonology", in Schneider, Edgar W. (ed.), A handbook of varieties of English, vol. 1, Berlin; New York: Mouton de Gruyter, pp. 1003–1015
Harrington, Cox & Evans (1997). Harrington, Jonathan; Cox, Felicity; Evans, Zoe (1997), "An acoustic phonetic study of broad, general, and cultivated Australian English vowels", Australian Journal of Linguistics, 17 (2): 155–184, doi:10.1080/07268609708599550
Watt & Allen (2003), pp. 268–269. Watt, Dominic; Allen, William (2003), "Tyneside English", Journal of the International Phonetic Association, 33 (2): 267–271, doi:10.1017/S0025100303001397
Peters (2006), p. 119. Peters, Jörg (2006), "The dialect of Hasselt", Journal of the International Phonetic Association, 36 (1): 117–124, doi:10.1017/S0025100306002428
Verhoeven (2007), p. 221. Verhoeven, Jo (2007), "The Belgian Limburg dialect of Hamont", Journal of the International Phonetic Association, 37 (2): 219–225, doi:10.1017/S0025100307002940