Fonte:
http://info.portaldasfinancas.gov.pt/NR/rdonlyres/8BB15371-82E1-4D9F-99A7-4ADFBEB3E17D/0/tratado%201698.pdf
http://info.portaldasfinancas.gov.pt/NR/rdonlyres/5CB444DE-5B08-42E9-9A73-EB203AAEC508/0/tratado%201801.pdf