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3. Bowen, G. H., and Beach, T. E. 1987, in Late Stages of Stellar Evolution, ed. S. Kwok and S. R. Pottasch (Dordrecht: Reidel), p. 275.
4. Brugel, E. W., Beach, T. E., Willson, L. A., and Bowen, G. H. 1988, in IAU Colloquium No. 103, The Symbiotic Phenomenon, ed. M. Friedjung (Dordrecht: Reidel), in press.
5. Castor, J. I. 1981, in Physical Processes in Red Giants, ed. I. Iben Jr. and A. Renzini (Dordrecht: Reidel), p. 285.