For this state of the art, details equivalent to those defined in G‑IV, 7.3.3 have to be determined if they are not clear from the written or other disclosure itself or if they are contested by a party.
If information is made available by means of a written description and use or by means of a written and oral description, but only the use or the oral description is made available before the relevant date, then in accordance with G‑IV, 1, the subsequently published written description may be deemed to give a true account of that oral description or use, unless the proprietor of the patent can give good reason why this should not be the case. In this case, the opponent must adduce proof to the contrary in respect of the reasons given by the proprietor of the patent. Caution should be exercised when considering the type of evidence presented to substantiate the content of an oral description. For example, a report of a lecture written by the lecturer himself may not be an accurate account of what was in fact conveyed to the public. Similarly, a script from which the lecturer purportedly read may not actually have been completely and comprehensibly read (see T 1212/97).
In opposition, if the publication date of a document originating from the opponent is in dispute, the opponent must prove that date beyond reasonable doubt. However, if the document is a brochure for advertising, it must be taken into account that such brochures are not normally kept secret for long after printing (T 2451/13).