References

• Beers T.C., Preston G.W., Schectman S.A., Doinidis S.P., Griffin K.E., 1992, AJ 103, 267 NASA ADS
• Dreizler S., 1993, A&A 273, 212 NASA ADS
• Drilling J.S., 1986, "Hydrogen-Deficient Stars and Related Objects", Hunger K., Schönberner S., Rao N.K. (eds.) p. 9
• Drilling J.S., 1996, "Hydrogen-Deficient Stars", Jeffery C.S., Heber U. (eds.), ASP Conf. Ser. 96, 461
• Drilling J.S., Jeffery C.S., Heber U., 1997, A&A (submitted)
• Green R.F., Schmidt M., Liebert J., 1986, ApJS 61, 305 NASA ADS
• Harrison P.M., Jeffery C.S., 1997, A&A 323, 177 NASA ADS
• Heber U., Jonas G., Drilling J.S., 1986, in "Hydrogen-deficient stars and related systems", IAU Coll. 87, Hunger K., Schönberner D., Rao N.K. (eds.). Reidel, Dordrecht, Holland
• Heber U., Dreizler S., de Boer K.S., Moehler S., Richtler T., 1988, Astron. Ges. Abs. Ser. 1, 16
• Heber U., Dreizler S., Werner K., Engels D., Hagen H.-J., 1996, "Hydrogen-Deficient Stars", Jeffery C.S., Heber U. (eds.), ASP Conf. Ser. 96, 241
• Husfeld D., Butler K., Heber U., Drilling J.S., 1989, A&A 222, 150 NASA ADS
• Jeffery C.S., 1996, "Hydrogen-Deficient Stars", Jeffery C.S., Heber U., ASP Conf. Ser. 96, 152
• Jeffery C.S. Heber U., 1992, A&A 260, 133 NASA ADS
• Jeffery C.S., Heber U., Hill P.W., et al., 1996, "Hydrogen-Deficicient Stars", Jeffery C.S., Heber U., ASP Conf. Ser. 96, 471
• Kilkenny D., Busse J., 1992, MNRAS 258, 57
• Moehler S., Richtler T., de Boer K.S., Dettmar R.J., Heber U., 1990, A&AS 86, 53 NASA ADS
• Morgan W.W., 1984, "The MK Process and Stellar Classification", Garrison R.F. (ed.), David Dunlap Observatory, p. 18
• Saffer R.A., Bergeron P., Koester D., Liebert J., 1994, ApJ 432, 351 NASA ADS
• Sargent W.L.W., Searle L., 1968, ApJ 152, 443 NASA ADS
• Schulz H., Heber U., Wegner G., 1991, PASP 103, 435 NASA ADS
• Sion E.M., 1996, "Hydrogen-Deficient Stars", Jeffery C.S., Heber U. (eds.), ASP Conf. Ser. 96, 223
• Stickland D.J., Lloyd C., 1994, Observatory 114, 41
• Thackeray A.D., 1970, MNRAS 150, 215 NASA ADS
• Theissen A., Moehler S., Heber U., de Boer K.S., 1993, A&A 273, 524 NASA ADS
• Thejll P., Bauer F., Saffer R., et al., 1994, ApJ 433, 819 NASA ADS
• Viton M., Deleuil M., Tobin W., Prévot L., Bouchet P., 1991, A&A 242, 175 NASA ADS
• Werner K., 1992, "The Atmospheres of Early-Type Stars", Heber U., Jeffery C.S. (eds.). Springer-Verlag, p. 273