Collection of CRS Reports on Immigration
Reports from the Congressional Research Service are in-depth and scholarly, unlike GAO and OIG reports which focus primarily on budget and fraud issues, respectively. CRS reports are intended for Congressional representatives and their staffers, and are not easily obtainable, unlike GAO and OIG reports which are available to the public on a variety of government websites. CRS reports on immigration are now available on ILW.COM on a handy page that you may wish to bookmark.
KJ