http://www.loc.gov/catdir/enhancements/fy0913/2009025027-b.html
http://www.loc.gov/catdir/enhancements/fy0913/2009025027-t.html
http://www.loc.gov/catdir/enhancements/fy0913/2009025027-d.html
http://assets.cambridge.org/97805217/67897/cover/9780521767897.jpg