Einstein observatory catalog of IPC x-ray sources  vol. 7 
Einstein Catalog Committee                                   
 - Cambridge  Smithsonian Astrophysical Observatory  1990 
 - iii, 510p. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>X-ray sources, Catalog-Imaging propotional counter.
<br/><br/><label>Universal Decimal Class. No.: </label>017:52-73  / EIN-7