Abud, M.Alcarás, J.A.CastilhoFerreira, P.Leal2022-04-292022-04-291980-02-01Lettere al Nuovo Cimento, v. 27, n. 7, p. 193-198, 1980.0375-930X1827-613Xhttp://hdl.handle.net/11449/231141193-198engArtigo10.1007/BF028171572-s2.0-51649166530