and CAS reached an agreement to increase cooperation in information exchange, which will improve their respective operations and service offerings. Under the agreement, Elsevier is providing enhanced electronic versions of its journal articles to CAS, and CAS in turn is helping Elsevier identify additional CAS Registry Numbers
in certain of its databases. The CAS Registry Number identification aspect of the agreement is being carried out periodically through an automated, first level, "machine comparison." That method is neither comprehensive nor detailed relative to many chemical structure conventions, and so this resulting addition of CAS Registry Numbers does not represent a complete comparison of Elsevier resources with the CAS REGISTRYSM
, the most comprehensive substance collection. Nonetheless, we anticipate these added CAS Registry Numbers will be useful and helpful for search and identification of more Elsevier database substances. From time to time more CAS Registry Numbers will be added.