Any health service corporation may enter into agreements with eligible persons whereby such persons become providers of a plan operated by the corporation. Any health service corporation may enter into contracts for the payment of health services to the subscribers or members of similar nonprofit health service corporations of other states subject to the supervision of such other states, or of counties of this state in which the corporation does not transact business. The corporation shall maintain in its office complete records of all health services rendered to subscribers and covered dependents in such form as will include the kind of services rendered, the amounts claimed for such services by the providers and the amount paid by the corporation.