Fonte:
http://www.dgaiec.min-financas.pt/NR/rdonlyres/40106DDE-5625-4F0A-B7AB-E14CBDD2354B/0/Circular_n_26_2011_II.pdf
http://www.dgaiec.min-financas.pt/NR/rdonlyres/5131DF74-C066-45C3-91E3-968F01460815/0/manual_procedimentos_iec_mar_2011_2.pdf
