@article{SD_1974-1975__28_1_A13_0,
     author = {Brzozowski, Janusz A.},
     title = {Hierarchies of aperiodic languages},
     journal = {S\'eminaire Dubreil. Alg\`ebre et th\'eorie des nombres},
     note = {talk:19},
     pages = {1--11},
     publisher = {Secr\'etariat math\'ematique},
     volume = {28},
     number = {1},
     year = {1974-1975},
     mrnumber = {395339},
     zbl = {0332.68056},
     language = {en},
     url = {http://www.numdam.org/item/SD_1974-1975__28_1_A13_0/}
}