Lavrov, Mikhail; Lee, Mitchell; Mackey, John (2014). «Improved upper and lower bounds on a geometric Ramsey problem». European Journal of Combinatorics42: 135–144. doi:10.1016/j.ejc.2014.06.003.
Exoo, Geoffrey (2003). «A Euclidean Ramsey Problem». Discrete & Computational Geometry29 (2): 223–227. doi:10.1007/s00454-002-0780-5. Exoo refers to the Graham & Rothschild upper bound N by the term "Graham's number". This is not the "Graham's number" G published by Martin Gardner.