References

• Bibo E.A., Thé P.S., 1991, A&AS 89, 319 NASA ADS
• Brand J., Wouterloot J.G.A., 1988, A&AS 75, 117 NASA ADS
• Chini R., Krügel E., 1983, A&A 117, 289 NASA ADS
• Chini R., Wargau W.F., 1990, A&A 227, 213 NASA ADS
• Grinin V.P., Thé P.S., de Winter D., et al., 1994, A&A 292, 165 NASA ADS
• Hester J., Scowen P., 1995, NASA Press Release No. 95-190
• Hillenbrand L.A., Massey P., Strom S.E., Merrill K.M., 1993, AJ 106, 1906 NASA ADS
• Horne K., 1986, PASP 98, 609 NASA ADS
• Jacoby G.H., Hunter D.A., Christian C.A., 1984, ApJS 56, 257 NASA ADS
• Johnson H.L., Borgman J., 1963, Bull. Astron. Neth. 17, 115
• Johnson H.L., 1966, ARA&A 4, 193
• Kamp L.W., 1974, A&AS 16, 1 NASA ADS
• Koulis C., 1993, Student Dissertation, Univ. of Amsterdam
• Kurucz R.L., 1991, Precision photometry; Astrophysics of the Galaxy, A.G. Davis Philip, A.R. Upgren, K.A Janes (eds.). L. Davis press, Schenectady, New York
• Lub J., Pel J.W., 1977, A&A 54, 137 NASA ADS
• Maeder A., Meynet G., 1988, A&AS 76, 411 NASA ADS
• Neckel Th., Chini R., 1981, A&AS 45, 451 NASA ADS
• Osterbrock D.E., 1974, Astrophysics of Gaseous Nebulae, Freeman and Company, San Fransisco
• Palla F., Stahler S.W., 1990, ApJ 360, L47 NASA ADS
• Palla F., Stahler S.W., 1992, ApJ 392, 667 NASA ADS
• Palla F., Stahler S.W., 1993, ApJ 418, 414 NASA ADS
• Pel J.W., 1987, Internal Rep. Leiden Obs
• Sagar R., Joshi U.C., 1979, Ap&SS 66, 3 NASA ADS
• Savage B.D., Mathis J.S., 1979, ARA&A 17, 73 NASA ADS
• Schmidt-Kaler Th., 1982, Landolt Börnstein Catalogue, Vol. VI/2b
• Steenman H., Thé P.S., 1989, Ap&SS 159, 189 NASA ADS
• Steenman H., Thé P.S., 1991, Ap&SS 184, 9 NASA ADS
• Thé P.S., Cuypers H., Tjin A Djie H.R.E., Feinstein A., Westerlund B.E., 1985, A&A 150, 345 NASA ADS
• Thé P.S., de Winter D., Feinstein A., Westerlund B.E., 1990, A&AS 82, 319 NASA ADS
• Thé P.S., de Winter D., Pérez M.R., 1993, A&AS 104, 315 NASA ADS
• Turner D.G., 1974, PhD Thesis, Univ. of Western Ontario, Canada
• Von Schewick H., 1962, Veroffentl. Sternwarte Bonn, No. 62
• Walker M.F., 1961, ApJ 133, 438 NASA ADS
• de Winter D., Thé P.S., 1991, MmSAI 62, 881 NASA ADS
• de Winter D., van den Ancker M.E., 1996, A&A (in press)