When assessing novelty, it is not permissible to "combine" separate items of prior art together. Only the actual content of a prior document as it would have been understood by a skilled person on its effective date can destroy novelty. In the case of a prior document according to Article 54(3), the effective date is the date of filing or the priority date of the said document. However, in a case such as the present, where the document according to Article 54(3) refers to "a usual manner" of preparing a product, it is permissible to use documents of reference such as handbooks, encyclopaedia or dictionaries in order to determine what the skilled person would have understood by such a reference on the effective date of the prior document.