author        = "Manfroid, J. and  Sterken, C. and  Bruch, A. and  Burger,
                       M. and  de Groot, M. and  Duerbeck, H. W. and  Duemmler, R.
                       and  Figer, A. and  Hageman, T. and  Hensberge, H. and 
                       Jorissen, A. and  Madejsky, R. and  Mandel, H. and  Ott, H.
                       A. and  Reitermann, A. and  Schulte-Ladbeck, R. E. and 
                       Stahl, O. and  Steenman, H. and  Vander Linden, D. and 
                       Zickgraf, F. J.",
      title         = "{Long-Term Photometry of Variables at ESO. I.}",
      year          = "1991",