Ondrej Klíma, Libor Polák
Hierarchies of Piecewise Testable Languages
DLT, 2010.
@article{DLT-J-2008-KlimaP10, author = "Ondrej Klíma and Libor Polák", doi = "10.1142/S0129054110007404", journal = "{International Journal of Foundations of Computer Science}", number = 4, pages = "517--533", publisher = "{World Scientific}", title = "{Hierarchies of Piecewise Testable Languages}", volume = 21, year = 2010, }