From the POC website,
Guidelines for nomination:1.) The books nominated either have to be by a Filipino author or published in the Philippines. For the purposes of this poll, any author with Filipino blood, even though he/she is not residing in the country, is considered a Filipino author.
2.) Each voter may nominate up to 100 books. Poetry, graphic novels and children's literature will be considered, as long as they are in book form and otherwise meet the criteria stated above.
3.) Comments and reasons for choosing particular books are welcome.