Accession to the share agreement by an owner of a labour stake shall be accompanied at all times by appropriate adherence to the unit`s company agreement, so that the interests can be considered bound by this agreement. Unless otherwise provided, subsequent accessions to this Agreement shall take effect with the AO from the date of deposit of the duly executed counterparties of any or all document necessary to justify an effective interest and/or treaty obligation in respect of this Agreement. . . .