Bellarosa, L.; Fowler, P. W.; Lijnen, E.; and Deza, M. "Addition Patterns in Carbon Allotropes: Independence Numbers and -Codes in the Klein and Related Graphs." J. Chem. Inf. Comput. Sci.44, 1314-1323, 2004.Ceulemans, A.; King, R. B.; Bovin, S. A.; Rogers, K. M.; Troisi, A.; and Fowler, P. W. "The Heptakisoctahedral Group and Its Relevance to Carbon Allotropes with Negative Curvature." J. Math. Chem.26, 101-123, 1999.DistanceRegular.org. "Klein Graph." https://www.math.mun.ca/distanceregular/graphs//klein.html.King, R. B. "Chemical Applications of Topology and Group Theory, 29, Low Density Polymeric Carbon Allotropes Based on Negative Curvature Structures." J. Phys. Chem.100, 15096-15104, 1996.King, R. B. "Novel Highly Symmetrical Trivalent Graphs Which Lead to Negative Curvature Carbon and Boron Nitride Chemical Structures." Disc. Math.244, 203-210, 2002.Klein, F. "Über die Transformationen siebenter Ordnung der elliptischen Funktionen." Math. Ann.14, 428-471, 1879. Reprinted in Gesammelte Mathematische Abhandlungen, 3: Elliptische Funktionen etc. (Ed. R. Fricke et al. ). Berlin: Springer-Verlag, pp. 90-136, 1973.Levy, S. (Ed.). The Eightfold Way: The Beauty of the Klein Quartic. New York: Cambridge University Press, 1999.
. This graph is illustrated above in four order-4 LCF notations. 
but is not distance-transitive. 
. 
-Codes in the Klein and Related Graphs." J. Chem. Inf. Comput. Sci. 44, 1314-1323, 2004.Ceulemans, A.; King, R. B.; Bovin, S. A.; Rogers, K. M.; Troisi, A.; and Fowler, P. W. "The Heptakisoctahedral Group and Its Relevance to Carbon Allotropes with Negative Curvature." J. Math. Chem. 26, 101-123, 1999.DistanceRegular.org. "Klein Graph."