In T 511/02, concerning the opponent's duty of substantiation, it had not been indicated when and how fitting and installation instructions cited against the patent had been made available to the public. Since this factor was crucial to the establishment of whether they formed part of the prior art and thus whether they could actually be cited against the patent, no adequate indication had been given of the relevant facts and evidence (see also T 1271/06 and T 109/11 for cases where the requirements of R. 55(c) EPC 1973 (R. 76(2)(c) EPC) were found not to be met; see T 1688/12 for a case where these requirements were considered to be fulfilled).

In T 782/04 the board noted however that the respondent had to apply a reasonable amount of understanding by reading the notice of opposition as required by the jurisprudence. In the case in hand the brochure produced by a company to illustrate a product to potential customers bore the notice "printed in Japan 73", whereas the priority date of the patent in suit was ca. 18 years later. The board considered that the allegations were sufficiently substantiated. The examination of whether the allegations were true was a question of evidence that was part of the examination of the allowability of the opposition. See also T 1236/13 (concerning documentation available on the internet) where the allegations as to which information carrier was used, the publication date and who was the public could be derived from document D6.

Where an oral disclosure is cited as prior art, the opposition division and the patent proprietor must be provided with sufficient details of the facts asserted and the supporting evidence to determine the date and content of the disclosure and the circumstances in which it was made public (T 406/92).