136In that regard, given that there is no legislation at EU level governing the concept of proof, the Courts of the European Union have laid down a principle of unfettered production of evidence or freedom as to the form of evidence adduced, which is to be interpreted as the right to rely, in order to prove a particular fact, on any form of evidence, such as oral testimony, documentary evidence, confessions, and so on (see, to that effect, judgments of 23 March 2000, Met-Trans and Sagpol, C‑310/98 and C‑406/98, EU:C:2000:154, paragraph 29; of 8 July 2004, Dalmine v Commission, T‑50/00, EU:T:2004:220, paragraph 72, and Opinion of Advocate General Mengozzi in Archer Daniels Midland v Commission, C‑511/06 P, EU:C:2008:604, points 113 and 114). Correspondingly, the Courts of the European Union have laid down a principle of the unfettered evaluation of evidence, according to which the determination of reliability or, in other words, the probative value of an item of evidence is a matter for those Courts (judgment of 8 July 2004, Dalmine v Commission, T‑50/00, EU:T:2004:220, paragraph 72, and Opinion of Advocate General Mengozzi in Archer Daniels Midland v Commission, C‑511/06 P, EU:C:2008:604, points 111 and 112).