diff --git a/Doc/user_guide.tex b/Doc/user_guide.tex
index d5c64dafa..94f5b6bf0 100644
--- a/Doc/user_guide.tex
+++ b/Doc/user_guide.tex
@@ -171,7 +171,10 @@ explain either solid state physics and its computational methods.
 If you want to learn the latter, you should read a good textbook, 
 such as e.g. the book by Richard Martin:
 {\em Electronic Structure: Basic Theory and Practical Methods},
-Cambridge University Press (2004). See also the ``Learn'' section in
+Cambridge University Press (2004); or
+{\em Density functional theory: a practical introduction}, 
+D. S. Sholl, J. A. Steckel (Wiley, 2009). 
+See also the ``Learn'' section in
 the \qe\ web site; the ``Reference Papers'' 
 section in the Wiki.