by Marie-Pierre Béal, Mikhail V. Berlinkov and Dominique Perrin
Reference:
A quadratic upper bound on the size of a synchronizing word in one-cluster automata (Marie-Pierre Béal, Mikhail V. Berlinkov and Dominique Perrin), In Int. J. Found. Comput. Sci., volume 22, 2011.
Bibtex Entry:
@Article{BealBerlinkovPerrin2011,
author = {Marie-Pierre B{\'e}al and Mikhail V. Berlinkov and Dominique Perrin},
title = {A quadratic upper bound on the size of a synchronizing word in one-cluster automata},
journal = {Int. J. Found. Comput. Sci.},
year = 2011,
volume = 22,
number = 2,
pages = {277–288},
url={http://igm.univ-mlv.fr/~beal/Recherche/Publications/cernyJournalFinal.pdf},
}