Carl Gustav Hempel - Essay with bibliography on this 20th-century thinker's life and ideas, by Mauro Murzi. From the Internet Encyclopedia of Philosophy.
Geometry and Empirical Science - Text of a 1945 paper by Hempel from the American Mathematical Monthly. Frameset with table of contents and text in separate frames.
On the Nature of Mathematical Truth - Text of Hempel's 1945 paper from the American Mathematical Monthly. Notes, table of contents, and text in separate frames.
The Doomsday Argument and Hempel's Problem - http://www.lawrence.edu/fac/boardmaw/Hempel_Emp_Crit.html Paper by Paul Franceschi, discussing Hempel's paradox of confirmation in detail, and a commonly-proposed solution to it.