Diaz, V. L. C., Salinas, J. T. I., & Colongon, A. A. J. (1989). Assessment of secondary materials on the provinces of Ifugao, Mountain Province and Nueva Vizcaya, 1978-1989. Cordillera Studies Center, University of the Philippines Baguio.

Diaz, Victoria Lourdes C., Jorge T. II Salinas, and Arellano A. Jr Colongon. Assessment of Secondary Materials on the Provinces of Ifugao, Mountain Province and Nueva Vizcaya, 1978-1989. Baguio City: Cordillera Studies Center, University of the Philippines Baguio, 1989.

Diaz, Victoria Lourdes C., et al. Assessment of Secondary Materials on the Provinces of Ifugao, Mountain Province and Nueva Vizcaya, 1978-1989. Cordillera Studies Center, University of the Philippines Baguio, 1989.