Fonte:
http://www.dgaiec.min-financas.pt/NR/rdonlyres/F73BFDF8-01AC-4742-B651-46B989DF9A01/0/Circular_n_84_2010_II.pdf
http://www.dgaiec.min-financas.pt/NR/rdonlyres/DC44C6F6-79BB-44CD-9594-33F1BA8C2D6E/0/Circular_n_83_2010_II.pdf
