Well quasi-orders, unavoidable sets, and derivation systems

D'Alessandro, Flavio; Varricchio, Stefano

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications, Volume 40 (2006) p. 407-426

A combinatorial theorem on $p$-power-free words and an application to semigroups

de Luca, Aldo; Varricchio, Stefano

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications, Volume 24 (1990) p. 205-228