From the U.S. Patent and Trademark Office (USPTO):
As part of the Global Dossier Initiative, the USPTO has released a beta version of the Citation List, a service that provides a comprehensive listing of relevant citations in related applications that share a common priority claim.
You can use the Citation List to view all references cited in the patent family of an application on a single page. In subsequent releases, we plan to introduce more features, such as viewing the citation publication documents and incorporating additional data sources to enhance the comprehensiveness and consistency of citation data.
Direct to Citation List