1. The contracting authority may specify in the procurement documents the elements of the technical specifications and the contract terms which constitute the minimum requirements and may not be subject to negotiation. The description of the subject-matter of public procurement and the contract terms shall be established by the contracting authority with sufficient precision to allow economic operators to identify the subject-matter and the nature of the public procurement, to decide whether or not they intend to submit a request to participate and to have equal opportunities to submit a suitable first tender in the tendering stage.
2. The contents of the invitation to tender shall be subject to Article 84(1), noting that the time limit for submission of tenders shall mean the time limit for submission of the first tender. Furthermore, the invitation to tender shall contain the process of negotiations and the related fundamental rules prescribed by the contracting authority and the date of the first negotiation.
3. The time limit for the submission of the first tender shall be set in accordance with Article 84(4)-(8).
4. In the negotiated procedure, the contracting authority shall be bound by the stipulations of the procurement documents, while the tenderer shall be bound by his tender from the date of conclusion of the negotiations. In the invitation to tender, the contracting authority may not set a validity period exceeding thirty - in case of public works, or where the procurement procedure is conducted under a control integrated in a process stipulated by a separate act of legislation, sixty - days from its commencement (the conclusion of negotiations).
5. Article 55(6) shall also be applied to tenders.
6. The contracting authority may decide, following the receipt of the first tenders, not to conduct negotiations and to complete the procedure by evaluating and assessing the tenders, if he indicated in the notice launching or announcing the procedure that he reserves the right to do so. In this case the contracting authority shall notify the tenderers of that decision without delay and the tenderers shall be bound by the validity period from the date of sending of that notification for the duration determined by the contracting authority, in accordance with the maximum durations foreseen in paragraph 4.
7. A final tender shall be submitted in a negotiated procedure, provided the contracting authority does not seize the opportunity under paragraph 6.