It is intended that the head contract («the Client / Consultant Agreement») is appended at Annexure A such that the Sub-Consultant will have its own copy of the Client / Consultant Agreement and can see the obligations therein undertaken by the Consultant and for which the Sub-Consultant is now engaged. The Client / Consultant Agreement appended at Annexure A need not include matters that do not concern the Sub-Consultancy Agreement and need not include commercial matters as between the Consultant and the Client. Annexure A does not form part of the Sub-Consultancy Agreement but is a document referred to therein that must be complied with in the same way as a code of practice or a building regulation. Whilst the Sub-Consultancy Agreement has been written specifically to facilitate the appointment of a Sub-Consultant where the Consultant is appointed under the FIDIC form of a Client / Consultant Agreement (the White Book) it may equally be used, with minimal amendments, where the head contract is not the White Book. Guidance on such usage will be published by FIDIC.