BRENNER, P. Initial Value Problems in $L_p$ for Systems with Variable Coefficients. MATHEMATICA SCANDINAVICA, [S. l.], v. 30, p. 141–149, 1972. DOI: 10.7146/math.scand.a-11070. Disponível em: https://www.mscand.dk/article/view/11070. Acesso em: 8 may. 2024.