More suggestions and sources
Howe, K. R. The quest for origins: who first discovered and settled New Zealand and the Pacific islands? Auckland: Penguin, 2003.
Simmons, D. R. The great New Zealand myth: a study of the discovery and origin traditions of the Maori. Wellington: A. H. & A. W. Reed, 1976.
Sorrenson, M. P. K. Maori origins and migrations. Auckland: Auckland University Press, 1979.