@article{JMPA_1925_9_4__169_0,
     author = {Williams, W. L. G.},
     title = {On the formal modular {Invariants} of binary {Forms}},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {169--192},
     publisher = {Gauthier-Villars},
     volume = {Ser. 9, 4},
     year = {1925},
     language = {en},
     url = {http://www.numdam.org/item/JMPA_1925_9_4__169_0/}
}