Franklyn T. Amistad, Norma A. Esguerra, and Alfredo R. Rabena. 1997. “Topographic Survey Comparison of Strategic Quarry Sites in Ilocos Sur”. The Vector: International Journal of Emerging Science, Technology and Management (IJESTM) 6 (1). https://doi.org/10.69566/ijestm.v6i1.111.