BELTITA, Ingrid; MELIN, Anders. Analysis of the quadratic term in the backscattering transformation. MATHEMATICA SCANDINAVICA, [S. l.], v. 105, n. 2, p. 218–234, 2009. DOI: 10.7146/math.scand.a-15116. Disponível em: https://tidsskrift.dk/math/article/view/15116. Acesso em: 13 aug. 2026.