Gray code orders for $q$-ary words avoiding a given factor
  Based on BRGC inspired order relations we give Gray codes and a generating algorithm for $q$-ary words avoiding a prescribed factor. These generalize an early 2001 result and a very recent one published by some of the present authors, and can be seen as an alternative to those of Squire published in 1996. Among the involved tools, we make use of generalized BRGC order relations, ultimate periodicity of infinite words, and word matching techniques. 
A. Bernini, S. Bilotta, R. Pinzani, A. Sabri and V. Vajnovszki
math.CO cs.DM