This bibliographic catalog is created by essentially matching scientific publications archived in the ADS with specific observations archived in the HEASARC. The papers can be refereed, unrefereed, or even arXiv preprints that have already been accepted or initially submitted for publication. Each observation in HEASARC's database tables has an ID parameter and each publication has a unique bibliographic reference code (bibcode), allowing a specific match to be made. The information in this table comes from correspondence from the author. This table is updated automatically shortly after the data is received. This is a service provided by NASA HEASARC .