Abstract: We note first that the first degree entailment of {\L}ukasiewicz's 3-valued logic and a 3-valued logic that is extracted of Belnap's 4-valued logic is the same. Then, we give an axiomatization of that entailment as the calculus E_{fde} + A &-A- > B\/-B, where E_{fde} is the first degree entailment of Anderson-Belnap's logic E of relevance and necessity.