Do you know where I can find an illustrated book about Filipino indigenous and tribal art, if any?

During my travels in the Philippines, I was able to recieve a pendant of an anito/bulol figure from someone as a souveneir. Since I have never seen or heard of such a figure, I have grown an interest to search for any form of sources or works that document as well as illustrate the works of indigenous Filipino art (espeically about Anito figures, baybayin and alibata, tribal tattoos, etc...). After arriving back home, I began my research and was surprised that there aren't as many sources of the topic as I have hoped.

Are there any books that document or illustrate these sort of stuff?