Bonds issued under this part may be secured by a pledge of, or lien upon the revenues and receipts derived from or with respect to the home mortgages or from or with respect to any notes or other obligations of lending institutions with respect to which the bonds have been issued, and the governing body of the issuing city or county may provide in the resolution authorizing such bonds for the issuance of additional bonds to be equally and ratably secured by a lien upon such revenues and receipts.