PAEPE, P. J. De. A maximal subalgebra of $R(X)$. Mathematica Scandinavica, Berkeley, CA, United States, v. 43, p. 322–324, 1978. DOI: 10.7146/math.scand.a-11784. Disponível em: https://journals.msp.org/mscand/article/view/1862. Acesso em: 25 jul. 2026.