Each of these databases provides access to a different type of scholarly article. All yield at least some results when searching the term "Polynesian warfare." (Try also individual island groups: Samoan warfare, and etc.) Databases marked with two asterisks (**) are only available to UH-Mānoa students, faculty and affiliates. Mouse over link for description.
Use COUNTRY -- Discovery and Exploration to find voyaging accounts. (Example. Hawaii -- discovery and exploration).
Use COUNTRY -- Description and Travel for the early post-voyaging accounts. (Example. Tonga -- discovery and travel).
Use COUNTRY -- Social life and customs for later descriptions, including modern works. (Example. Samoa -- social life and customs).
Use Ethnology -- COUNTRY for later descriptions, including modern works. (Example. Ethnology -- French Polynesia.)
4. Google Books