4.__Trust indenture. In the discretion of the directors, the bonds may be secured by a trust indenture by and between the authority and a corporate trustee, which may be any trust company or bank having the powers of a trust company, located either within or outside the State.__The trust indenture may pledge or assign the revenues of the authority or any part of it. Any indenture may set forth the rights and remedies of the bondholders and the trustee, may restrict the individual right of action of bondholders and may contain any other provisions the directors may determine reasonable and proper for the security of bondholders. Expenses incurred in carrying out any trust indenture may be treated as a part of maintenance.

5.__Rights of bondholders. Provisions may be made for protecting and enforcing the rights and remedies of the bondholders, including covenants as to acquisition of property, construction, maintenance, operation and repair, insurance and the custody, security and application of all funds.

6.__Depositories. Any trust company or bank having the powers of a trust company and located either within or outside the State may act as depositories of the proceeds of the bonds and revenue and may furnish indemnity or pledge such securities as may be required by the authority.

7.__Tax free. The purposes of this chapter being public and for the benefit of the people of the State, the authority bonds are free from taxation by the State.

8.__Revenue refunding bonds. The authority may issue revenue refunding bonds for the purpose of refunding the revenue bonds issued under this chapter. The issuance of any refunding bonds must be the same as provided for in this chapter relating to revenue bonds.

9.__Default. In the event of default on the bonds and in the event the default continues for a period of 3 months, action may be brought to enforce the rights of the bondholders by ensuring that the operation by the directors is in conformity with the covenants of the bonds or indenture.