$uvby-\beta$ photoelectric photometry of the open clusters NGC 6811 and   NGC 6830
  From $uvby-\beta$ photometry of the open clusters NGC 6811 (75 stars), and NGC 6830 (19 stars) we were able to determine membership of the stars to each cluster, and fix the age and reddening for each. Since several short period stars have recently been found, we have carried out a study of these variables. 
J.H. Pena, L. Fox Machado, H. Garcia, A. Renteria, S. Skinner, A.   Espinosa, E. Romero
astro-ph.SR