BERGSTRÖM, H. Some Remarks on an Algebraic Identity. MATHEMATICA SCANDINAVICA, [S. l.], v. 8, p. 39–42, 1960. DOI: 10.7146/math.scand.a-10589. Disponível em: https://www.mscand.dk/article/view/10589. Acesso em: 2 may. 2024.