H. Neilson, L. Rousseau-Nepton, S. Lawler, and K. Spekkens. (2019)cite arxiv:1910.02976Comment: 11 pages. Community paper submitted to the Canadian Long Range Plan 2020, https://casca.ca/?page_id=11499lrp2020/.
P. Hilfinger, E. Lawler, and G. Rote. Applied Geometry And Discrete Mathematics, volume 4 of DIMACS Series in Discrete Mathematics and Theoretical Computer Science, page 335-340. DIMACS/AMS, (1990)