NG, Kung-fu. On a Computation Rule for Polars. MATHEMATICA SCANDINAVICA, [S. l.], v. 26, p. 14–16, 1970. DOI: 10.7146/math.scand.a-10962. Disponível em: https://www.mscand.dk/article/view/10962. Acesso em: 5 dec. 2025.