1. A computer-implemented method comprising: determining a plurality of potential countries of origin of a document by examining one or more factors associated with the document; determining a country of origin of the document by selecting a country from the plurality of potential countries as being the most likely country of origin for the document; processing the document, using the determined country of origin of the document, to determine a numeric or alphanumeric sequence of characters in the document to establish a call by: recalling rules relating to a format of said sequence associated with the determined country of origin of the document; and searching the document to identify a sequence in the document satisfying said format of the determined country of origin of the document; determining that said sequence is not associated with any country prefix; determining a country prefix associated with the selected country of origin; appending said sequence to include the country prefix; and returning the appended sequence for association with the document.