diff --git a/debug.opts b/debug.opts
index 338c71c009291d3b593f2a6d9f1360d746ea58ca..925e0ffb07f346e5c5bc9bffd7fd5215075a27f1 100644
--- a/debug.opts
+++ b/debug.opts
@@ -16,13 +16,15 @@ GXX_OPTS=" \
     -fstrict-overflow \
     -g"
 
-USE_CMAKE=yes
-
+# configure flags
 CMAKE_FLAGS="\
   -DCMAKE_CXX_FLAGS=\"$GXX_WARNING_OPTS $GXX_OPTS\" \
   "
 
-# for CO2 and CO2ni tests
+# optional configure flags
+# for the CO2 and CO2ni tests enable the experimental grid extension
+# and make sure the module dune-alugrid is present
 # -DDUNE_GRID_EXPERIMENTAL_GRID_EXTENSIONS=TRUE \
-# need to be set in the configure flags
-# and the module dune-alugrid must be present
+
+# for using gstat
+# -DGSTAT_ROOT=gstat_installation_path \
diff --git a/doc/handbook/4_externaltools.tex b/doc/handbook/4_externaltools.tex
index ba942f92841c391adbad528f90a42e37547ddd5d..5d2233cb2348ce5574a50fab0faf726bce46493c 100644
--- a/doc/handbook/4_externaltools.tex
+++ b/doc/handbook/4_externaltools.tex
@@ -1,6 +1,17 @@
 \section{External Tools}
 \label{sc_externaltools}
 
+\subsection{Eclipse}
+There is an Eclipse style file which can be used for \Dumux.
+\begin{enumerate}
+  \item open in eclipse: \texttt{Window} $\rightarrow$ \texttt{Preferences} $\rightarrow$
+        \texttt{C/C++}  $\rightarrow$ \texttt{Code Style} $\rightarrow$ \texttt{Formatter}
+  \item press the \texttt{Import} button
+  \item choose the file \texttt{eclipse\_profile.xml} from your dumux-devel directory
+  \item make sure that now \Dumux is chosen in \texttt{Select a profile}
+\end{enumerate}
+
+
 \subsection{Git}
 Git is a version control tool which we use.
 The basic Git commands are:
@@ -17,15 +28,20 @@ The basic Git commands are:
   a commit
 \end{itemize}
 
-\subsection{Eclipse}
-There is an Eclipse style file which can be used for \Dumux.
-\begin{enumerate}
-  \item open in eclipse: \texttt{Window} $\rightarrow$ \texttt{Preferences} $\rightarrow$
-        \texttt{C/C++}  $\rightarrow$ \texttt{Code Style} $\rightarrow$ \texttt{Formatter}
-  \item press the \texttt{Import} button
-  \item choose the file \texttt{eclipse\_profile.xml} from your dumux-devel directory
-  \item make sure that that now \Dumux is chosen in \texttt{Select a profile}
-\end{enumerate}
+
+\subsection{Gnuplot}
+A gnuplot interface is available to plot or visualize results during a simulation run.
+This is achieved with the help of the class provided in \texttt{io/gnuplotinterface.hh}.
+Have a look at tests including this header for examples how to use this interface.
+
+
+\subsection{Gstat}
+Gstat is an open source software tool which generates geostatistical random fields (see \url{www.gstat.org}).
+In order to use gstat, execute the \texttt{bin/installexternal.sh} from your \Dumux root
+directory or donwload, unpack and install the tarball from the gstat-website.
+Then rerun cmake (in the second case set \texttt{GSTAT\_ROOT} in your input file to the
+path where gstat is installed).
+
 
 \subsection{Kate}
 For kate there is syntax highlighting style for \Dumux input files. Simply
@@ -33,11 +49,12 @@ copy the file \texttt{dumux-devel/dumux\-InputFiles.xml} to the \texttt{syntax}
 your kate configuration directory (e.g.
 \texttt{HOME/.kde4/share/apps\-/katepart/syntax/dumuxInputFiles.xml}).
 
+
 \subsection{ParaView}
 \paragraph{Reload Button:}
 There are scripts to reload \texttt{*.pvd} or series of {\texttt{*.vtu} files since ParaView 4.2.
 The scripts can be found
-\href{http://markmail.org/message/exxynsgishbvtngg#query:+page:1+mid:rxlwxs7uqrfgibyv+state:results}{\texttt{under this lin}}.
+\href{http://markmail.org/message/exxynsgishbvtngg#query:+page:1+mid:rxlwxs7uqrfgibyv+state:results}{\texttt{under this link}}.
 Just save the specific code portion in a file and load it via \texttt{Macros} $\rightarrow$ \texttt{Add new macro}.
 
 \paragraph{Guide:}
diff --git a/dumux/material/spatialparams/gstatrandomfield.hh b/dumux/material/spatialparams/gstatrandomfield.hh
index 8f8fe9b010f3b4133c6f16fa391ccd651cabc4b3..33289d2097351dba75624f1614ddb0484d54d976 100644
--- a/dumux/material/spatialparams/gstatrandomfield.hh
+++ b/dumux/material/spatialparams/gstatrandomfield.hh
@@ -19,6 +19,7 @@
 /*!
  * \file
  *
+ * \ingroup SpatialParameters
  * \brief Creating random fields using gstat
  */
 #ifndef DUMUX_GSTAT_RANDOM_FIELD_HH
@@ -33,13 +34,16 @@ namespace Dumux
 {
 
 /*!
+ * \ingroup SpatialParameters
  * \brief Creating random fields using gstat
  *
  * gstat is an open source software tool which can (among other things) generate
- * geostatistical random fields (see <a href="www.gstat.org">www.gstat.org</a>).
+ * geostatistical random fields (see <a href="http://www.gstat.org">http://www.gstat.org</a>).
  *
- * To use this class, unpack and install the zipped gstat tarball from the website
- * or use the script installexternal.sh provided with dumux.
+ * To use this class, execute the installexternal.sh from your DuMuX root
+ * directory or donwload, unpack and install the tarball from the gstat-website.
+ * Then rerun cmake (in the second case set GSTAT_ROOT in your input file to the
+ * path where gstat is installed).
  */
 template<class GridView, class Scalar>
 class GstatRandomField
@@ -55,17 +59,18 @@ public:
     // Add field types if you want to implement e.g. tensor permeabilities.
     enum FieldType { scalar, log10 };
 
-    /*!\brief Constructor.
+    /*!
+     * \brief Constructor.
      *
      * Creates a new field with random variables, if desired.
      * Otherwise creates a data field from already available data.
      *
-     * For the a rand field generation three files are necessary.
+     * For the random field generation three files are necessary.
      * A \a gstatControlFile in which all commands and in/output files for gstat are specified.
      * A \a gstatInputFile contains all coordinates (cell centers) of the grid, so that
      * gstat can perform its random realization. The filename must be same as in the gstatControlFile.
      * A \a gstatOutputFile in which gstat writes the random values to this file.
-     * The filename must be same as in the gstatControlFile.
+     * The filename must be the same as in the gstatControlFile.
      *
      * \param gridView the used gridView
      * \param gstatControlFile name of control file for gstat
diff --git a/optim.opts b/optim.opts
index bb7499ca78ccec1ece2c3ef82bc88b4c6623718d..937f720422b23f302814f4f42824fa659f327e08 100644
--- a/optim.opts
+++ b/optim.opts
@@ -19,14 +19,15 @@ GXX_OPTS=" \
     -march=native \
     -DNDEBUG=1"
 
-USE_CMAKE=yes
-
-# configure flags 
+# configure flags
 CMAKE_FLAGS=" \
   -DCMAKE_CXX_FLAGS=\"$GXX_WARNING_OPTS $GXX_OPTS\" \
   "
 
-# for CO2 and CO2ni tests
+# optional configure flags
+# for the CO2 and CO2ni tests enable the experimental grid extension
+# and make sure the module dune-alugrid is present
 # -DDUNE_GRID_EXPERIMENTAL_GRID_EXTENSIONS=TRUE \
-# need to be set in the CMake flags
-# and the module dune-alugrid must be present
+
+# for using gstat
+# -DGSTAT_ROOT=gstat_installation_path \