1. Some earlier papers did provide overviews of the entire field, e.g. particularly Grace (1968) and Pawley (1972), as well as some of the articles in Sebeok (1971). Reference to other regional surveys will be made later in this article.
2. Of course, scholars found other motivations too, the desire to spread religion not least among them.
3. Recognition of the limitations of the family tree model is evident in works such as Pawley and Green (1984), and Ross (1988). See Ross (1988:7-11) for a discussion of how these different means of language diversification can be represented pictorially.
4. Ross himself says that Proto-Western Oceanic is not quite a proto-language in the commonly accepted way.