Immigration: the Demographic and Economic Facts
by Julian Simon 1995
Total per capita government expenditures on immigrants are much lower than those for natives, no matter how immigrants are classified. Narrowly defined welfare expenditures for immigrants are slightly more than for natives, but this has been true in the past, too. These welfare expenditures are only small fractions of total government expenditures on immigrants and natives. Schooling costs and payments to the elderly are the bulk of government expenditures; natives use more of these programs, especially Social Security and Medicare.
Cato Institute

Immigration
by George J. Borjas 2002
Immigration is again a factor of demographic change in the USA.
Library of Economics and Liberty - Liberty Fund

The Stranger who Sojourns with You: Toward a Moral Immigration Policy
by Andrew M. Yuengert 2004
The Catholic social tradition consistently asserts a very broad right to migrate; this perspective immediately transforms the debate.
Acton Institute