Article 4
1. Free-at-frontier prices shall be determined for each place of origin on the basis of all available information and particularly of the notifications from Member States. The latter shall for this purpose use primarily the information contained in customs documents accompanying imported products and in invoices and other trade documents. They shall notify the Commission daily of the prices recorded for each normal commercial quantity and for each place of origin when the goods cross the Community frontier. 2. Account shall also be taken when determining free-at-frontier prices of any other information concerning prices applied by third countries, and namely the following: (a) export prices of third countries, (b) prices recorded on importation into the Community, (c) prices noted on the markets of exporting third countries. 3. The following sources shall be used when seeking information: (a) official information published by the competent authorities of exporting third countries, (b) information published by the specialist trade press in the Member States and in third countries, (c) information supplied by professional and trade organizations and by producers' and traders' representatives in the Member States and in third countries.