Jeffrey Shallit, Ming-wei Wang. On Two-Sided Infinite Fixed Points of Morphisms. In Gabriel Ciobanu, Gheorghe Paun, editors, Fundamentals of Computation Theory, 12th International Symposium, FCT 99, Iasi, Romania, August 30 - September 3, 1999, Proceedings. Volume 1684 of Lecture Notes in Computer Science, pages 488-499, Springer, 1999. [doi]
Abstract is missing.