APA

Ferreira F. A., .Exprressiveness and definability in circumscription. : .

Chicago

Ferreira F.M-Martins A.T, .Exprressiveness and definability in circumscription. : .

Harvard

Ferreira F. A., .Exprressiveness and definability in circumscription. : .

MLA

Ferreira F.M-Martins A.T, .: . .