Cheng, L., Kotoulas, S., Ward, T., & Theodoropoulos, G. (2014). A two-tier index architecture for fast processing large RDF data over distributed memory. In HT'14 : proceedings of the 25th ACM Conference on Hypertext and Social Media : September 1-4, 2014, Santiago, Chile (300-302). https://doi.org/10.1145/2631775.2631789