A rate-distortion theorem without reference letters

We show the asymptotic attainability of R(D) without assuming reference letters. We modify a scheme of T. Hashimoto (see IEEE Trans. Inform. Theory, vol.29, p.785-92, Nov. 1983) and prove a coding theorem for a stationary abstract-alphabet source only assuming an auxiliary source. The coding scheme proposed can be extended to time-continuous sources since no facts in ergodic theory are used.