UPDATE: The problem described below has been fixed.
Because of a computer malfunction at the U.S. Government Printing Office, many of the links from our catalogs to online versions of U.S. documents are not working. The GPO is working on the problem, but it may take some time to repair.
Meanwhile, we recommend searching Google using the title of the document and the agency that produced it. This will often lead to a working online version.
Also, of course, our catalogs list many printed versions of documents, available in the Cal libraries.