Cunha, C. (2002). "Cunhal, Àlvaro" (2 pp.); "Left Bloc (BE)" (3 pp.); "Portuguese   Communist   Party   (PCP)"   (4   pp.); "Portuguese   Socialist   Party   (PS)”(4   pp.). In Wheeler, Douglas L. (Ed.), Historical Dictionary of Portugal. Lanham, MD (EUA): Scarecrow Press.