[1]
Albertson, M.O., Chappell, G.G., Kierstead, H.A., Kündgen, A. and Ramamurthi, R. 2004. Coloring with no $2$-Colored $P_4$’s. The Electronic Journal of Combinatorics. 11, 1 (Mar. 2004), R26. DOI:https://doi.org/10.37236/1779.