ebrary, Inc, Kügler, F., Féry, C., & Vijver, R. F. H. E. v. d. (2009). Variation and gradience in phonetics and phonology. Mouton de Gruyter.
芝加哥风格引文ebrary, Inc, Frank Kügler, Caroline Féry, 与 Ruben Florentius Hendricus Eduardus van de Vijver. Variation and Gradience in Phonetics and Phonology. New York, NY: Mouton de Gruyter, 2009.
MLA引文ebrary, Inc, et al. Variation and Gradience in Phonetics and Phonology. Mouton de Gruyter, 2009.
警告：这些引文格式不一定是100％准确.