Clustering in the X-ray Universe
  In this paper we discuss various possibilities of using X-ray observations to gain information about the large-scale structure of the Universe. After reviewing briefly the current status of these investigations we explore different ways of making progress in this field, using deep surveys, large area surveys and X-ray background observations. 
X. Barcons (1), F.J. Carrera (2 and 1), M.T. Ceballos (1), S. Mateos   (1) ((1) Instituto de Fisica de Cantabria CSIC-UC, (2...