Right-cancellability of a family of operations on binary trees. Duchon, Philippe — 1998 Discrete Mathematics and Theoretical Computer Science. DMTCS [electronic only]
Enumeration of alternating sign matrices of even size (quasi-)Invariant under a quarter-turn rotation. Aval, Jean-Christophe; Duchon, Philippe — 2010 The Electronic Journal of Combinatorics [electronic only]