According to Silke Hamann, it cannot be clearly determined whether Czech has a retroflex fricative or not, as the articulations differ too much. – Hamann, Silke (2004). "Retroflex fricatives in Slavic languages". Journal of the International Phonetic Association. pp. 53–67. Retrieved 20 March 2022.
archive.org
Dankovičová (1999:70) Dankovičová, Jana (1999), "Czech", Handbook of the International Phonetic Association: A guide to the use of the International Phonetic Alphabet, Cambridge: Cambridge University Press, pp. 70–74, ISBN0-521-65236-7
Dankovičová (1999:73) Dankovičová, Jana (1999), "Czech", Handbook of the International Phonetic Association: A guide to the use of the International Phonetic Alphabet, Cambridge: Cambridge University Press, pp. 70–74, ISBN0-521-65236-7
