Combinatorics of the free Baxter algebra. Aguiar, Marcelo; Moreira, Walter — 2006 The Electronic Journal of Combinatorics [electronic only]
The associative operad and the weak order on the symmetric groups. Aguiar, Marcelo; Livernet, Muriel — 2007 Journal of Homotopy and Related Structures
Canonical characters on quasi-symmetric functions and bivariate Catalan numbers. Aguiar, Marcelo; Hsiao, Samuel K. — 2005 The Electronic Journal of Combinatorics [electronic only]