| 2008 | - | Primate social knowledge and the origins of language - Seyfarth,Cheney | :: | |
| Hurford JD (1990) Beyond the roadblock in linguistic evolution studies. Behav Brain Sci 13:736-737
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| 2002 | - | Did language evolve like the vertebrate eye? - Botha | :: | |
| Hurford, J.R., 1990. Beyond the roadblock of linguistic evolution studies. Behavioral and Brain Sciences 13, 736-737.
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