On the closed left ideals of the group algebra C S n Dias da Silva, J.A. — 1980 Portugaliae mathematica
On matrix groups defined by certain polynomial identities Oliveira, Graciano N. de; Dias da Silva, J.A. Portugaliae mathematica
On the notion of transversal of a sum of matroids Cordovil, Raúl; Dias da Silva, J.A.; Fonseca, Amélia — 1988 Portugaliae mathematica