@article{00721223, title = {Counting two-graphs related to trees.}, journal = {The Electronic Journal of Combinatorics [electronic only]}, volume = {2}, year = {1995}, zbl = {0810.05031}, language = {en}, url = {http://dml.mathdoc.fr/item/00721223} }
Cameron, Peter J. Counting two-graphs related to trees.. The Electronic Journal of Combinatorics [electronic only], Tome 2 (1995) . http://gdmltest.u-ga.fr/item/00721223/