Kenyon, Richard W., and David B. Wilson. “Combinatorics of Tripartite Boundary Connections for Trees and Dimers”. The Electronic Journal of Combinatorics 16, no. 1 (September 11, 2009): R112. Accessed March 16, 2026. https://www.combinatorics.org/ojs/index.php/eljc/article/view/v16i1r112.