Each DP camp received a set of DP 1 cards. These cards were printed with sequential numbers consisting of one letter and eight numerals. The letter indicated the country in which the person was registered: for example, G for Germany or A for Austria. These registration numbers were only issued once. On the DP 3 cards, this number was entered in the first field. The number is the same on all documents for a specific person. Family members were given sequential numbers if possible.