[doc][handbook] Add information on how to obtain suitesparse

doc/handbook/3_detailedinstall.tex

@@ -243,6 +243,8 @@ has to be called from your common root directory.
 
 
 \subsection{List of External Libraries and Modules}
+\label{sec:listofexternallibs}
+
 In the following list, you can find some external modules and external libraries,
 and some more libraries and tools which are prerequisites for their use.
 
@@ -276,6 +278,7 @@ and supports periodic boundary conditions.
   Download: \url{http://crd.lbl.gov/~xiaoye/SuperLU}
 
 \item \textbf{UMFPack}: External library for solving linear equations. It is part of SuiteSparse.
+  See: \url{http://faculty.cse.tamu.edu/davis/suitesparse.html}. On Debian/Ubuntu you can install the package \texttt{libsuitesparse-dev}.
 
 \item \textbf{dune-UG}: External library for use as grid. UG is a toolbox for unstructured grids, released under GPL.
   To build UG the tools \texttt{lex}/\texttt{yacc} or the GNU variants of \texttt{flex}/\texttt{bison} must be provided.