One of the most important moments is the preparation of detailed documentaion. For every catalog we provide the detailed and maximum full scientific text in separate files, describing the telescope, calibration of observations, columns of tables, etc., from the original paper publications.
These text files are marked as hypertext for the easy access from the WWW software. The main list of CATS catalogs has, as a rule, references to original ones or to the site of initial storage, and ftp-access to every catalog. In our database we also used catalogs typed from original paper. But in some cases we corrected the typos or errors in initial texts. Sometimes we used the ``latex2html'' software for obtaining hupertext files from available LaTex text.