Fonte:
http://www.dgci.min-financas.pt/NR/rdonlyres/CC935941-E150-463D-8D89-6845E82D6F06/0/OficCirc_90013.pdf
http://www.dgci.min-financas.pt/NR/rdonlyres/BE7A71C0-D6EC-4E0F-A832-50539AB92E62/0/Of_Circ_201292008_DSIRS.pdf
