1. S.L. Anderson, T. Hirooka, P.W. Tiedeman, B.H. Mahan, Y.T. Lee, J. Chem. Phys. 43, 4779 (1980)
2. J. Schäfer, Europhys. Lett. 34, 69 (1996)
3. D. Pfenniger, F. Combes, L. Martinet, Astron. Astrophys. 285, 79 (1994)
4. D. Pfenniger, F. Combes, Astron. Astrophys. 285, 94 (1994)
5. E.L. Wright, in Back to the Galaxy, ed. by S.S. Holt, F. Verter (AIP, New York, 1993), p. 193