5. Factual data sources

The main need for chemical information expressed by end-users is direct access to numerical and factual data for the exploitation of experimental results and for scientific calculation. Sources of such data are either monographic or specialized by property type. Beilstein, Gmelin and Hodoc, previously described, as well as the Landolt-Börnstein tables (handbook on numerical data on functional relationship in science and technology published by Springer Verlag) are first-rate general sources. Access to factual data has been described in detail in various articles belonging to other Techniques de l'Ingénieur treatises: L'accès à l'information factuelle [1] , Bases et banques de données en thermodynamique [2] , Sources d'information en chimie analytique