JENSEN, A. Some remarks on eigenfunction expansions for Schrödinger operators with non-local potentials. MATHEMATICA SCANDINAVICA, [S. l.], v. 41, p. 347–357, 1977. DOI: 10.7146/math.scand.a-11727. Disponível em: https://www.mscand.dk/article/view/11727. Acesso em: 29 apr. 2024.