1. Morpurgo-Davies A (1998) History of Linguistics.Vol. IV: Nineteenth-Century Linguistics. London and New York: Longman, 464 pp.
2. Darwin C (1871) The Descent of Man, and Selection in Relation to Sex. London: John Murray, 423 pp.
3. Frank RM (2008) The language-organism-species analogy: A complex adaptive systems approach to shifting perspective on ‘language’. In: M FR, Dirven R, Ziemke T, Bernárdez E, editors, Body, Language and Mind. Vol. 2. Sociocultural Situatedness, Berlin: Mouton de Gruyter. 215–262.
4. Nettle D, Romaine S (2000) Vanishing voices: The extinction of the world’s languages. Oxford: Oxford University Press, 243 pp.
5. Crystal D (2002) Language death. Cambridge University Press, 210 pp.