Consult:
- Declaration on CTT's Analytical Accounting System - 2005 https://www.anacom.pt/render.jsp?contentId=821818
- Declaration on CTT's Analytical Accounting System - 2006 https://www.anacom.pt/render.jsp?contentId=821801
See also:
- Notice no. 4006/2009, published on 19 February https://www.anacom.pt/render.jsp?contentId=859459