@article{ITA_1981__15_3_233_0, author = {Brandstadt, Andreas}, title = {Closure properties of certain families of formal languages with respect to a generalization of cyclic closure}, journal = {RAIRO. Informatique th\'eorique}, pages = {233--252}, publisher = {EDP-Sciences}, volume = {15}, number = {3}, year = {1981}, mrnumber = {630064}, zbl = {0467.68066}, language = {en}, url = {http://www.numdam.org/item/ITA_1981__15_3_233_0/} }