Fonte:
http://www.dgaiec.min-financas.pt/NR/rdonlyres/9A397AD0-FB17-4C8A-8F00-40AA4FD49C90/0/Circular_43_2007_II.pdf
http://www.dgaiec.min-financas.pt/NR/rdonlyres/9EA914B1-DC64-49E0-BAD8-001B3B0FCABA/0/Circular_n_78_2007_II.pdf
