We present a comparison of Abell and Automated Plate Measuring Facility ( APM ) clusters of galaxies as tracers of the large scale structure of the Universe .
We investigate selection functions of both cluster catalogs , using samples of all clusters ( including clusters with estimated redshifts ) , and samples of clusters with measured redshifts .
We find that the distribution of rich superclusters , defined by all Abell and APM clusters , is similar in volume covered by both cluster samples .
We show that the supercluster-void network can be traced with both cluster samples ; the network has a well-defined period of \sim 120 h ^ { -1 } Mpc .
We calculate the correlation function for Abell and APM cluster samples .
However , the APM cluster sample with measured redshifts covers a small volume which contains only a few very rich superclusters .
These superclusters surround one void and have exceptionally large mutual separations .
Due to this property the secondary maximum of the correlation function of APM clusters with measured velocities is located at larger scales than corresponding feature in the correlation function of Abell clusters .
We conclude that the APM sample is not representative for the large-scale structure as a whole due to the small space coverage .
The Abell cluster catalog is presently the best sample to investigate the large-scale distribution of high-density regions in the Universe .
We present a catalog of superclusters of galaxies , based on APM clusters up to a redshift z _ { lim } = 0.13 .