Jean Berstel Clelia de Felice Dominique Perrin Christophe Reutenauer Giuseppina Rindone Recent results on syntactic groups of prefix codes. 1386-1401 2012 33 Eur. J. Comb. 7 http://dx.doi.org/10.1016/j.ejc.2012.03.004 db/journals/ejc/ejc33.html#BerstelFPRR12