The challenge of this thesis is to cross over a troublesome situation: the classifying separation between a poetry supposed to be purely expressive - understood as a no elaborated writing, able to reveal something from the authors life - and another one, purely constructive - understood as a controlled object, far from writers emotion and from his immediate reality. In this way, one affirms from the critical-poetical universe of the marginal poetry written in the seventies (70s) - dialogues and battles with/against authorities (authors and labels) that became canonized around the referred dichotomy, in other words, one deals with a tense, careful and delirious crossing. With no intention to deny the forces of the construction and of the expression, one realizes an operation of leakage - a traitor / trickster operation - in its possible channels of totality.