Fonte:
http://www.dgci.min-financas.pt/NR/rdonlyres/DD2049F6-3609-47DB-95BA-BD5A0E4CEB96/0/Circular%2008-2008.PDF
http://www.dgci.min-financas.pt/NR/rdonlyres/E1EF9FA0-AF91-4D83-B8FC-F4E6FA73130B/0/Circular%2009-2008.PDF
http://www.dgci.min-financas.pt/NR/rdonlyres/3DC881EC-5D65-4279-8C65-ED922DF7A7A4/0/Circular%2010-2008.PDF
http://www.dgci.min-financas.pt/NR/rdonlyres/12B11B5F-AABF-42E2-A23A-DF06397316AC/0/Circular%2011-2008.PDF
http://www.dgci.min-financas.pt/NR/rdonlyres/25CC7278-E304-4C86-86A5-9148086261FB/0/Circular%2012-2008.PDF
