[handbook] cleanup

doc/handbook/5_models.tex

@@ -124,7 +124,7 @@ $\boldsymbol{v}_\alpha$ & velocity (Darcy or free flow)& & \\
 
 
 \subsection{Gas mixing laws}
-Prediction of the $p-\varrho-T$ behavior of gas mixtures is typically based on the following two (contradicting) concepts: Dalton's law or Amagat's law.
+Prediction of the $p-\varrho-T$ behavior of gas mixtures is typically based on two (contradicting) concepts: Dalton's law or Amagat's law.
 In the following the two concepts will be explained in more detail.
 %
 \subsubsection{Dalton's law}