PUBLIC LAW 102-139—OCT. 28, 1991 105 STAT. 777 current fiscal year for purchase of uniforms, or allowances therefor, as authorized by law (5 U.S.C. 5901-5902); hire of passenger motor vehicles; and services as authorized by 5 U.S.C. 3109. SEC. 503. Funds of the Department of Housing and Urban Development subject to the Government Corporation Control Act or section 402 of the Housing Act of 1950 shall be available, without regard to the limitations on administrative expenses, for legal services on a contract or fee basis, and for utilizing and making payment for services and facilities of Federal National Mortgage Association, Government National Mortgage Association, Federal Home Loan Mortgage Corporation, Federal Financing Bank, Resolution Trust Corporation, Federal Reserve banks or any member thereof. Federal Home Loan banks, and any insured bank within the meaning of the Federal Deposit Insurance Corporation Act, as amended (12 U.S.C. 1811-1831). SEC. 504. No part of any appropriation contained in this Act shall remain available for obligation beyond the current fiscal year unless expressly so provided herein. SEC. 505. No funds appropriated by this Act may be expended— (1) pursuant to a certification of an officer or employee of the United States unless— (A) such certification is accompanied by, or is part of, a voucher or abstract which describes the payee or payees and the items or services for which such expenditure is being made, or (B) the expenditure of funds pursuant to such certification, and without such a voucher or abstract, is specifically authorized by law; and (2) unless such expenditure is subject to audit by the General Accounting Office or is specifically exempt by law from such audit. SEC. 506. None of the funds provided in this Act to any department or agency may be expended for the transportation of any officer or employee of such department or agency between his domicile and his place of employment, with the exception of any officer or employee authorized such transportation under title 31, United States Code, section 1344. SEC. 507. None of the funds provided in this Act may be used for payment, through grants or contracts, to recipients that do not share in the cost of conducting research resulting from proposals not specifically solicited by the Government: Provided, That the extent of cost sharing by the recipient shall reflect the mutuality of interest of the grantee or contractor and the Government in the research. SEC. 508. None of the funds provided in this Act may be used, directly or through grants, to pay or to provide reimbursement for payment of the salary of a consultant (whether retained by the Federal Government or a grantee) at more than the daily equivalent of the maximum rate paid for GS-18, unless specifically authorized bylaw. SEC. 509. No part of any appropriation contained in this Act for personnel compensation and benefits shall be available for other object classifications set forth in the budget estimates submitted for the appropriations: Provided, That this section shall not apply to any part of the appropriations contained in this Act for Offices of Inspector General personnel compensation and benefits.