(67)It should be clarified that electronic auctions are typically not suitable for certain public works contracts and certain public service contracts having as their subject-matter intellectual performances, such as the design of works, because only the elements suitable for automatic evaluation by electronic means, without any intervention or appreciation by the contracting authority, namely elements which are quantifiable so that they can be expressed in figures or percentages, may be the object of electronic auctions. It should, however, also be clarified that electronic auctions may be used in a procurement procedure for the purchase of a specific intellectual property right. It is also appropriate to recall that while contracting authorities remain free to reduce the number of candidates or tenderers as long as the auction has not yet started, no further reduction of the number of tenderers participating in the electronic auction should be allowed after the auction has started.