A good initial reference for on-line services is Albrecht and Egret (1991) and a new version of this book is currently nearing completion.
A distinction is made in this paper between
The different on-line services described below offer one or more of these items and they are listed under what they predominantly support. The institutions providing these services are often referred to as ``data centers''. One may broadly speak of large, general purpose data centers (like NASA-NSSDC, of which the ``Astronomical Data Center'' (ADC) is just a part, and the CDS Strasbourg), medium-sized regional data centers (e.g. in Moscow, Tokyo, LaPlata, Beijing, Pune, etc.) and mission-oriented data centers like IPAC, ESRIN, ESTEC, STScI, and many others. The latter have mainly been set up in recent times due to the enormous amount of data produced by space missions.