Optical and X-ray clusters as tracers of the supercluster-void network.   II The spatial correlation function
  We study the space distribution of Abell and X-ray selected clusters of galaxies from the ROSAT Bright Source Catalog, and determine correlation functions for both cluster samples. On small scales the correlation functions depend on the cluster environment: clusters in rich superclusters have a larger correlation length and amplitude than all clusters. On large scales correlation functions depend on the distribution of superclusters. On these scales correlation functions for both X-ray and Abell clusters are oscillating with a period of ~115 h^{-1} Mpc. This property shows the presence of a dominating scale in the distribution of rich superclusters. 
E. Tago, J. Einasto, M. Einasto, V. M"uller and H. Andernach