The authority of this part may be used to issue bonds for the purpose of financing residential rehabilitation in areas which were designated for concentrated code enforcement and have received federal funds under the Federally Assisted Code Enforcement program (Sections 115, 117, and 312 of the Housing Act of 1949, 42 U.S.C. 1466, 1468, and 1452b), and nothing in this part shall prevent using funds generated by bonds issued pursuant to the provisions of this part to finance residential rehabilitation in such areas.