Spirkin, A.G.
The origin of language
[Publisher not identified], [Date of publication not identified]
 Buku Teks SO
Hazen, Kirk
An introduction to language
Massachusetts : Wiley Blackwell, 2015
 Buku Teks SO
Hughes, John P.
The science of language: an introduction to linguistics
Random House, 1966
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Nerlich, Brigitte
Change in language : Whitney, Breal, and Wagener
Routledge, 1990
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Linguistics : the cambridge survey; Volume IV language : The socio-cultural context
edited by Frederick J. Newmeyer
Cambridge University Press, 1990
 Buku Teks SO