Recasens 2004, p. 436 citando Fougeron 1999 e Browman et al. 1995 Recasens, Daniel (2004), «The effect of syllable position on consonant reduction (evidence from Catalan consonant clusters)», Journal of Phonetics, 32 (3): 435–453, doi:10.1016/j.wocn.2004.02.001 Fougeron, C (1999), «Prosodically conditioned articulatory variation: A Review», UCLA Working Papers in Phonetics, 97, pp. 1–73 Browman, C.P.; Goldstein, L. (1995), «Gestural syllable position in American English», in: Bell-Berti, F.; Raphael, L.J., Producing Speech: Contemporary Issues: for Katherine Safford Harris, New York: AIP, pp. 9–33
Hallé, Best & Levitt 1999, p. 283 citando Delattre et al. 1968, Zawadzki et al. 1980, e Boyce et al. 1997 Hallé, Pierre A.; Best, Catherine T.; Levitt, Andrea (1999), «Phonetic vs. phonological influences on French listeners' perception of American English approximants», Journal of Phonetics, 27 (3): 281–306, doi:10.1006/jpho.1999.0097 Delattre, P.; Freeman, D.C. (1968), «A dialect study of American R's by x-ray motion picture», Linguistics, 44: 29–68 Zawadzki, P.A.; Kuehn, D.P. (1980), «A cineradiographic study of static and dynamic aspects of American English /r/», Phonetica, 37 (4): 253–266, PMID7443796, doi:10.1159/000259995 Boyce, S.; Espy-Wilson, C. (1997), «Coarticulatory stability in American English /r/», Journal of the Acoustical Society of America, 101 (6): 3741–3753, PMID9193061, doi:10.1121/1.418333
Hallé, Best & Levitt 1999, p. 283 citando Delattre et al. 1968, Zawadzki et al. 1980, e Boyce et al. 1997 Hallé, Pierre A.; Best, Catherine T.; Levitt, Andrea (1999), «Phonetic vs. phonological influences on French listeners' perception of American English approximants», Journal of Phonetics, 27 (3): 281–306, doi:10.1006/jpho.1999.0097 Delattre, P.; Freeman, D.C. (1968), «A dialect study of American R's by x-ray motion picture», Linguistics, 44: 29–68 Zawadzki, P.A.; Kuehn, D.P. (1980), «A cineradiographic study of static and dynamic aspects of American English /r/», Phonetica, 37 (4): 253–266, PMID7443796, doi:10.1159/000259995 Boyce, S.; Espy-Wilson, C. (1997), «Coarticulatory stability in American English /r/», Journal of the Acoustical Society of America, 101 (6): 3741–3753, PMID9193061, doi:10.1121/1.418333