@article{GDZPPN002191393, title = {The number of archiral trees.}, journal = {Journal f\"ur die reine und angewandte Mathematik}, volume = {272}, year = {1975}, pages = {322-335}, zbl = {0311.05102}, url = {http://dml.mathdoc.fr/item/GDZPPN002191393} }
Harary, Frank; Robinson, Robert W. The number of archiral trees.. Journal für die reine und angewandte Mathematik, Tome 272 (1975) pp. 322-335. http://gdmltest.u-ga.fr/item/GDZPPN002191393/