Fonte:
http://info.portaldasfinancas.gov.pt/NR/rdonlyres/55124C9E-58A0-4F3C-B4A8-D0C10F523C53/0/inf%201965.pdf
http://info.portaldasfinancas.gov.pt/NR/rdonlyres/4DD08FF9-B340-4C11-837A-1F677F836E37/0/inf%202157.pdf