A/RES/53/29 Page 3 8. Decides further that, in accordance with the provisions of its resolution 973 (X) of 15 December 1955, there shall be set off against the apportionment among Member States, as provided for in paragraph 7 above, their respective share in the Tax Equalization Fund of the estimated staff assessment income of 316,300 dollars approved for the Observer Mission for the period from 13 July 1998 to 13 January 1999; 9. Decides, as an ad hoc arrangement, to apportion the amount of 9,073,400 dollars gross 8,669,500 dollars net) among Member States for the period from 14 January to 30 June 1999 at a monthly rate of 1,620,250 dollars gross (1,548,125 dollars net), in accordance with the scheme set out in the present resolution and taking into account the scale of assessments for the year 1999, as set out in its resolution 52/215 A, subject to the decision of the Security Council to extend the mandate of the Observer Mission beyond 13 January 1999; 10. Decides also that, in accordance with the provisions of its resolution 973 (X) , there shall be set off against the apportionment among Member States, as provided for in paragraph 9 above, their respective share in the Tax Equalization Fund of the estimated staff assessment income of 403,900 dollars approved for the Observer Mission for the period from 14 January to 30 June 1999; 11. Invites voluntary contributions to the Observer Mission in cash and in the form of services and supplies acceptable to the Secretary-General, to be administered, as appropriate, in accordance with the procedure and practices established by the General Assembly; 12. Decides to keep under review during its fifty-third session the agenda item entitled "Financing of the United Nations Observer Mission in Sierra Leone". 64th plenary meeting 20 November 1998