Cox (2006:?) Cox, F.M. (2006), "The acoustic characteristics of /hVd/ vowels in the speech of some Australian teenagers", Australian Journal of Linguistics, 26: 147–179, doi:10.1080/07268600600885494, S2CID62226994
Durie & Hajek (1994:?) Durie, M.; Hajek, J. (1994), "A revised standard phonemic orthography for Australian English vowels", Australian Journal of Linguistics, 14 (1): 93–107, doi:10.1080/07268609408599503
Iivonen & Harnud (2005:62, 66–67) Iivonen, Antti; Harnud, Huhe (2005), "Acoustical comparison of the monophthong systems in Finnish, Mongolian and Udmurt", Journal of the International Phonetic Association, 35 (1): 59–71, doi:10.1017/S002510030500191X, S2CID145733117
Jassem (2003:105) The source transcribes this sound with the symbol ⟨ɨ⟩ but one can see from the vowel chart at pag. 105 that the Polish sound is closer to [ɘ] than to [ɨ]. Jassem, Wiktor (2003), "Polish", Journal of the International Phonetic Association, 33 (1): 103–107, doi:10.1017/S0025100303001191
Cox (2006:?) Cox, F.M. (2006), "The acoustic characteristics of /hVd/ vowels in the speech of some Australian teenagers", Australian Journal of Linguistics, 26: 147–179, doi:10.1080/07268600600885494, S2CID62226994
Iivonen & Harnud (2005:62, 66–67) Iivonen, Antti; Harnud, Huhe (2005), "Acoustical comparison of the monophthong systems in Finnish, Mongolian and Udmurt", Journal of the International Phonetic Association, 35 (1): 59–71, doi:10.1017/S002510030500191X, S2CID145733117