References

• Bruhweiler F.C., 1987, ApJ 317, 152 NASA ADS
• Carter B.S., 1990, MNRAS 242, 1 NASA ADS
• Caraveo P.A., Bignami G.F., Goldwurm A., 1989, ApJ 338, 338 NASA ADS
• Coe M.J., Roche P., Everall C., et al., 1994a, MNRAS 270, L57 NASA ADS
• Coe M.J., Roche P., Everall C., et al., 1994b, A&A 289, 784-794 NASA ADS
• Coe M.J., Fabregat J., Negueruela I., Roche P., Steele I.A., 1996, MNRAS 281, 333 NASA ADS
• Dennerl K., Haberl F., Pietsch W., 1996, Proceedings Wurzburg Conference, MPE Report 263, 131
• Gezari D.Y., Schmitz M., Pitts P.S., 1994, Catalog of Infrared Observations, NASA Pub RP-1294, 3rd edition
• Glass I.S., 1979, MNRAS 187, 807 NASA ADS
• Glass I.S., 1985, Irish Astron. J. 17, 1 NASA ADS
• Glass I.S., Feast M.W., 1973, Nat Phys. Sci. 245, 39
• Haberl F., Dennerl K., Pietsch W., 1995a, A&A 302, L1 NASA ADS
• Haberl F., Pietsch W., Dennerl K., 1995b, A&A 303, 49
• Hughes J.P., 1994, ApJ 427, L25 NASA ADS
• Hughes J.P., Smith R.C., 1994, AJ 107, 1363 NASA ADS
• Ilovaisky S.A., Chevalier C., Motch C., 1982, A&A 114, L7 NASA ADS
• Johnston M.D., Bradt H., Doxsey R.E., 1979, ApJ 233, 514 NASA ADS
• Kahabka P., Pietsch W., 1996, A&A 312, 919 NASA ADS
• Kaper L., Lamers H.J.G.L.M., Ruymakers E., et al., 1995, A&A 300, 466
• Long K.S., Helfand D.J., Grabelsky D.A., 1981, ApJ 248, 925 NASA ADS
• Mereghetti S., Belloni T., Shara M., Drissen L., 1994, ApJ 424, 943 NASA ADS
• Motch C., Pakull M., Haberl F., Dennerl K., 1996, IAU Circ. 6285
• Pakull M., Brunner H., Pietsch W., et al., 1985, Space Sci. Rev. 40, 379 NASA ADS
• Schmidtke P.C., Cowley A.P., Frattare L.M., et al., 1994, PASJ 106, 843
• Southwell K.A., Charles P.A., 1996, MNRAS (in press)
• Stevens J.B., Reig P., Coe M.J., et al., 1997, MNRAS (in press)
• Stollberg M.T., Finger M.H., Wilson R.B., et al., 1993, IAU Circ. 5836
• Tuohy I.R., Buckley D.A.H., Remillard R.A., Bradt H.V., Schwartz D.A., 1988, unpublished paper presented at the "Physics of Neutron, Strs & Black Holes'' Conference, Tokyo, Feb. 1988
• van der Klis M., van Paradijs J., Charles P.A., et al., 1983, MNRAS 203, 279 NASA ADS
• Yamauchi S., et al., 1995, PASJ 47, 189 NASA ADS