BLEYER, A. EXAMPLES, COUNTER-EXAMPLES AND APPLICATIONS TO THE THEORY OF OPERATOR TRANSFORMATI ONS Periodica Polytechnica Electrical Engineering, [S. l.], v. 21, n. 2, p. 163–173, 1977. Disponível em: https://pp.bme.hu/ee/article/view/4884. Acesso em: 16 may. 2024.