The European Patent EP 1 720 284 B1 (https://register.epo.org/application?number=EP05752399) had been attacked by an Opposition under Art. 100(a) EPC (lack of patentability) as the only Opposition ground. Six prior art documents were mentioned in the Opposition Brief, but only document A1 was used in the detailed lack of patentability arguments. The Opponent had provided a copy of A1 (a non-patent document without publication date) together with the indication "Copyright Notice 2003”, but no further explanations. The Patentee argued that document A1 was not properly identified and the Opposition therefore not sufficiently substantiated, since the Opposition Brief did not present any details about the circumstances and time point of the publication of A1. The Opposition Division followed these arguments and declared the Opposition as inadmissible since it did not contain sufficient indication of facts and evidence as requested by Rule 76(2)(c) EPC (in line with T0511/02 of the BoA of the EPO). An Appeal was not filed.