... The Einstein On­Line Service (EOLS) is a simple menu­ driven system which provides an intuitive method of querying over one hundred database catalogs. ... The EOLS provides all of our databases to the NASA Astrophysics Data System (ADS) and our documents which describe each table are written in the ADS format. In conjunction with the IAU working group on Radioastronomical Databases, the EOLS serves as an experi­ mental platform for on­line access to radio source catalogs. ...