String Matching And Algorithmic Problems In Free Groups. Klaus Madlener; Jürgen Avenhaus — 1980 Revista colombiana de matematicas
On expressing commutativity by finite Church-Rosser presentations : a note on commutative monoids Jürgen Avenhaus; Ronald V. Book; Craig C. Squier — 1984 RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications