Okada (1999),第117頁. Okada, Hideo, Japanese, International Phonetic Association (编), Handbook of the International Phonetic Association: A Guide to the Use of the International Phonetic Alphabet, Cambridge University Press: 117–119, 1999, ISBN 978-0-52163751-0
Adams (1975),第285–286頁. Adams, Douglas Q., The Distribution of Retracted Sibilants in Medieval Europe, Language, 1975, 51 (2): 282–292, JSTOR 412855, doi:10.2307/412855
Adams (1975),第285–286頁. Adams, Douglas Q., The Distribution of Retracted Sibilants in Medieval Europe, Language, 1975, 51 (2): 282–292, JSTOR 412855, doi:10.2307/412855
UPSID r[F. [24 January 2016]. (原始内容存档于2019-01-06).
uta.edu
Zimmer & Orgun (1999),第154頁. Zimmer, Karl; Orgun, Orhan, Turkish(PDF), Handbook of the International Phonetic Association: A guide to the use of the International Phonetic Alphabet, Cambridge: Cambridge University Press: 154–158, 1999 [2021-03-16], ISBN 978-0-521-65236-0, (原始内容(PDF)存档于2018-07-25)
Zimmer & Orgun (1999),第154頁. Zimmer, Karl; Orgun, Orhan, Turkish(PDF), Handbook of the International Phonetic Association: A guide to the use of the International Phonetic Alphabet, Cambridge: Cambridge University Press: 154–158, 1999 [2021-03-16], ISBN 978-0-521-65236-0, (原始内容(PDF)存档于2018-07-25)