If a party raises a ground for nullity the assessment of which involves the skilled person his
common general knowledge, this party bears the corresponding burden of allegation, i.e. it
must specifically name the skilled person (defined according to education and/or profession)
and his common general knowledge (in particular the extent of the pertinent technical
knowledge supposed to be known to him at the relevant date). If such a specific allegation is
not put forward the ground for nullity will be dismissed (R. 19-20 and 31-32).