Slamet, Santosa, Tadahiro Matsumoto, Tohru Naoi, and Munehiro Goto. 2015. “Sector-Labeling for the Hilbert Curve Construction and Its Application to Mapped Data Retrieval Algorithms”. Science & Technology Asia 7 (3):49-57. https://ph02.tci-thaijo.org/index.php/SciTechAsia/article/view/41793.