[handbook] Minor changes in sequential tutorial

doc/handbook/3_tutorialsequential.tex

@@ -119,14 +119,14 @@ a problem class is attached to the new type tag, while the grid which
 is going to be used is defined in line \ref{tutorial-sequential:set-grid-type} --
 in this case an \texttt{YaspGrid} is created. Since there's no uniform mechanism to
 allocate grids in \Dune, \Dumux features the concept of grid creators.
-In this case the generic \texttt{CubeGridCreator} (line \ref{tutorial-sequential:set-gridcreator}) which creates a
+In this case the generic \texttt{CubeGridCreator} which creates a
 structured hexahedron grid of a specified size and resolution. For
 this grid creator the  physical domain of the grid is specified via the
 run-time parameters \texttt{Grid.UpperRight} and
 \texttt{Grid.Cells}. These parameters can be specified via
 the command-line or in a parameter file.
 For more information about the \Dune grid interface, the different grid types
-that are supported and the generation of different grids consult
+that are supported and the generation of different grids, consult chapter \ref{sec:gridhandling} of this document and
 the \textit{Dune Grid Interface HOWTO} \cite{DUNE-HP}.
 
 Next, we select the material of the simulation: In the case of a pure two-phase