The Kernel Category and Variants of the Concatenation Product. - Mário J. J. Branco (Int. J. Algebra Comput., 1997)

Two algebraic approaches to variants of the concatenation product. - Mário J. J. Branco (Theor. Comput. Sci., 2006)

Equations Defining the Polynomial Closure of a Lattice of Regular Languages. - Mário J. J. Branco; Jean-Eric Pin (ICALP (2), 2009)

Left Adequate and Left Ehresmann Monoids. - Mário J. J. Branco; Gracinda M. S. Gomes; Victoria Gould (Int. J. Algebra Comput., 2011)

Inequalities for One-Step Products. - Mário J. J. Branco; Jean-Éric Pin (DLT, 2018)