1. Chayer, P., Fontaine, G., Wesemael, F., & Michaud, G.: 1987, in IAU Colloquium 95, The Second Conference on Faint Blue Stars, ed(s)., A.G.D. Philip, D.S. Hayes, & J. Liebert, L. Davis Press, Schenectady, 653.
2. Chayer, P., Fontaine, G., & Wesemael, F.: 1989, in IAU Colloquium 114, White Dwarfs, ed(s)., G. Wegner, (New York: Springer), 253.
3. Chayer, P., Fontaine, G., & Wesemael, F.: 1991, in White Dwarfs, ed(s)., G. Vauclair and E. Sion, NATO ASI Series, Series C, no. 336, (Dordrecht: Kluwer), 249.
4. Morvan, E., Vauclair, G., & Vauclair, S.: 1986, Astr. Ap.
163, 145.
5. Pelletier, C., Fontaine, G., & Wesemael, F.: 1989, in IAU Colloquium 114, White Dwarfs, ed(s)., G. Wegner, (New York: Springer), 249.