J. Sawada, A. Williams. A Universal Cycle for Strings with Fixed-Content (Which Are Also Known as Multiset Permutations). In Anna Lubiw, Mohammad R. Salavatipour, editors, Algorithms and Data Structures - 17th International Symposium, WADS 2021, Virtual Event, August 9-11, 2021, Proceedings. Volume 12808 of Lecture Notes in Computer Science, pages 599-612, Springer, 2021. [doi]