| 2005 | - | Isolating-Monocategorial-Associational Language - Gil | :: | 1 |
| 2002 | - | A Syntactic Rule in Forest Monkey Communication - Zuberbuhler | :: | 8 |
| 1990 | - | Grammatical Combination in Pan Paniscus: Processes of Learning and Invention in the Evolution and Development of Language - Greenfield,Savage-Rumbaugh | :: | 3 |
| 1990 | - | Language and Species - Bickerton | :: | 87 |
| 1990 | - | The Cognitive Foundations for Reference in a Signing Orangutan - Miles | :: | 2 |