For more detail on U.S. literacy, see A First Look at the Literacy of America's Adults in the 21st century, U.S. Department of Education (2003).
Truy cập ngày 1 tháng 8 năm 2006.  ^ For more detail on U.S. literacy, see A First Look at the Literacy of America’s Adults in the 21st century, U.S. Department of Education (2003). ^ “Human Development Indicators” (PDF).