Encyclopedias are an excellent resource to find background information on a topic. Here are a few Encyclopedias that may be of use in locating background information on "immigration reform"
Britannica Online consists of a fully searchable and browsable collection of authoritative references, including Britannica's latest article database, hundreds of articles. n
Credo Reference is a digital reference library that places a world of factual information at your fingertips. Containing a selection from 240 high-quality reference books from the world's leading publishers, Credo Reference is the ideal place to start any research.
Publications from CQ Press dating back to 1945, a total of 110 reference works, including directories, encyclopedias, handbooks, compendia, yearbooks, etc.
Sage e-Reference is a full-text collection of over 80 online specialized encyclopedias in the social sciences, including communications, gender studies, social work, history, psychology, etc. Search one encyclopedia, or all of them simultaneously.