Consult:
- Report on the Quality System of the Universal Postal Service of CTT - 2006 https://www.anacom.pt/render.jsp?contentId=759598
- Report on the Quality System of the Universal Postal Service of CTT - 2007 https://www.anacom.pt/render.jsp?contentId=759823
See also:
- Notice no. 3911/2009, published on 18 February (referent to the year 2006 and 2007) https://www.anacom.pt/render.jsp?contentId=859399