Bergeron, N., C. Hohlweg, M. Rosas, and M. Zabrocki. “Grothendieck Bialgebras, Partition Lattices, and Symmetric Functions in Noncommutative Variables”. The Electronic Journal of Combinatorics 13, no. 1 (August 25, 2006): R75. Accessed April 4, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v13i1r75.