M.M. Halldórsson and M. Szegedy, Lower Bounds for On-line Graph Coloring, Theoretical Computer Science 130, 163-174, 1994
the authors prove a lower bound for the performance function which is better than the bound given on page 173 in Graph Coloring Problems by a factor of 2, that is, they prove
ρA(n) ≥ 2n / (log n)2
More details can be found in the abstract.September 1997, T.R. Jensen.