@article{JRAM_1975__0278_0279_151661,
     author = {Frank Harary and Robert W. Robinson},
     title = {The number of archiral trees.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {322--335},
     publisher = {mathdoc},
     volume = {0278_0279},
     year = {1975},
     zbl = {0311.05102},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1975__0278_0279_151661/}
}