@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 - Theoretical Informatics and Applications - Informatique Th\'eorique et Applications},
     pages = {233--252},
     publisher = {EDP-Sciences},
     volume = {15},
     number = {3},
     year = {1981},
     mrnumber = {630064},
     zbl = {0467.68066},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ITA_1981__15_3_233_0/}
}