MELIN, Anders. A Remark on Invariant Pseudo-Differential Operators. Mathematica Scandinavica, Berkeley, CA, United States, v. 30, p. 290–296, 1972. DOI: 10.7146/math.scand.a-11085. Disponível em: https://journals.msp.org/mscand/article/view/2239. Acesso em: 25 jul. 2026.