1. Bellitto, T., Pêcher, A., Sèdillot, A.: On the density of sets of the Euclidean plane avoiding distance 1 (2018).
arXiv:1810.00960v1
2. Cranston, D.W., Rabern, L.: The fractional chromatic number of the plane. Combinatorica 37(5), 837–861 (2017)
3. de Grey, A.D.N.J.: The chromatic number of the plane is at least $$5$$. Geombinatorics 28(1), 18–31 (2018)
4. Exoo, G., Ismailescu, D.: A unit distance graph in the plane with fractional chromatic number 383/102. Geombinatorics 26(3), 122–127 (2017)
5. Graph Data.
http://cs.indstate.edu/ge/ExooIsmailescuData