The Award authority has chosen the competitive procedure with subsequent negotiations because the service to be provided is of such a nature that it will not be possible to specify in detail the exact nature of the service. The choice of the best offer may not, therefore be made pursuant to the provisions for open or restricted tender, and regulations on public procurement § 14-3. The event is at the planning stage and in a more specific framework for event and pricing will have to be made in co-operation with suppliers, as part of negotiations.