The XMM-Newton/Chandra monitoring campaign of the Galactic center region - Description of the program and preliminary results
R. Wijnands, J. J. M. in 't Zand, M. Rupen, T. Maccarone, J. Homan, R. Cornelisse, R. Fender, J. Grindlay, M. van der Klis, E. Kuulkers, C. B. Markwardt, J. C. A. Miller-Jones and Q. D. Wang
