@article{1183530218, author = {Waterman, Daniel}, title = {$W$-systems are the Walsh functions}, journal = {Bull. Amer. Math. Soc.}, volume = {75}, number = {5}, year = {1969}, pages = { 139-142}, language = {en}, url = {http://dml.mathdoc.fr/item/1183530218} }
Waterman, Daniel. $W$-systems are the Walsh functions. Bull. Amer. Math. Soc., Tome 75 (1969) no. 5, pp. 139-142. http://gdmltest.u-ga.fr/item/1183530218/