The ASCA Hard Serendipitous Survey
  We summarize here some of the main results we have reached so far in the ASCA Hard Serendipitous Survey, a survey program conducted in the 2-10 keV energy band. In particular we will discuss the number-flux relationship, the 2-10 keV spectral properties of the sources, and the cross-correlation of the ASCA sources with ROSAT sources. 
R. Della Ceca, V. Braito, I. Cagnoni and T. Maccacaro