[web] TM; Add citation; fix formula for rendering.

use pandoc, not md, because of formula rendering.

web/content/docs/benchmarks/thermo-mechanics/thermomechanics.pandoc

@@ -15,23 +15,27 @@ weight = 156
 
 ## Problem description
 
-We solve a thermo-mechanical homogeneous model in cube domain. The dimensions of this cube model are 1\,m in all directions. The boundary conditions and temperature loadings, as well as the material can refer Chapter 14 in Kolditz et al. for detailed problem description.
+We solve a thermo-mechanical homogeneous model in cube domain. The dimensions of
+this cube model are 1 m in all directions. The boundary conditions and
+temperature loadings, as well as the material can refer Chapter 14 in Kolditz et
+al. \cite Kolditz2012 for detailed problem description.
 
 ## Results and evaluation
 
-Result showing temperature and stresses development with time in the centre node of the model:
+Result showing temperature and stresses development with time in the centre node
+of the model:
 
 {{< img src="../temperature.png" >}}
 {{< img src="../stress.png" >}}
 
 The analytical solution of stresses after heating is:
-$$
-\begin{equation}
-\sigma_{xx} = \sigma_{yy} = \sigma_{zz} = - \frac{\alpha \Delta T E}{1 - 2 \nu} = - 3.260869\, \mathrm{MPa}
-\end{equation}
-$$
+$$\begin{equation}
+\sigma_{xx} = \sigma_{yy} = \sigma_{zz} = - \frac{\alpha \Delta T E}{1 - 2 \nu}
+= - 3.260869\, \textrm{MPa}
+\end{equation}$$
 
-The relative error between the numerical simulation and the analytical solution is $9.2 \cdot 10^{-13}$.
+The relative error between the numerical simulation and the analytical solution
+is 9.2<span class="math inline">⋅10<sup>-13</sup></span>.
 
 ## References