diff --git a/examples/1ptracer/doc/1pintro.md b/examples/1ptracer/doc/1pintro.md
index 2a6e6b9e80c60d12aa088911bc440f714e898195..61a8f95eedf92ef5fe9628b553e7ea4bb5800438 100644
--- a/examples/1ptracer/doc/1pintro.md
+++ b/examples/1ptracer/doc/1pintro.md
@@ -8,4 +8,8 @@ settings for the simulation. Two exemplary `properties`, that are mandatory to b
 specialized, are `Problem` and `SpatialParams`. With the first, one sets the
 `Problem` class to be used, in which users can define initial and boundary conditions.
 Similarly, in the `SpatialParams` class one implements the parameter distributions
-(e.g. porosity and permeability) that should be used.
+(e.g. porosity and permeability) that should be used by the model.
+
+The documentation provided in the sequel is structured as follows:
+
+[[_TOC_]]
diff --git a/examples/1ptracer/doc/tracerintro.md b/examples/1ptracer/doc/tracerintro.md
index f26897906eedb5a15cc4b808cbad730437f6018f..9b64df8053674d60f52afae69e3bb65c6e7ddc5a 100644
--- a/examples/1ptracer/doc/tracerintro.md
+++ b/examples/1ptracer/doc/tracerintro.md
@@ -8,4 +8,8 @@ settings for the simulation. Two exemplary `properties`, that are mandatory to b
 specialized, are `Problem` and `SpatialParams`. With the first, one sets the
 `Problem` class to be used, in which users can define initial and boundary conditions.
 Similarly, in the `SpatialParams` class one implements the parameter distributions
-(e.g. porosity and permeability) that should be used.
+(e.g. porosity and permeability) that should be used by the model.
+
+The documentation provided in the sequel is structured as follows:
+
+[[_TOC_]]
diff --git a/examples/1ptracer/main.cc b/examples/1ptracer/main.cc
index cd51ba9f35f85c1831163ee07227d77cf5cdd4d0..b1c6b23f88752f431aee14777a2bab70d690e46b 100644
--- a/examples/1ptracer/main.cc
+++ b/examples/1ptracer/main.cc
@@ -17,14 +17,15 @@
  *   along with this program.  If not, see <http://www.gnu.org/licenses/>.   *
  *****************************************************************************/
 
-// ## Main program flow (`main.cc`)
+// # Main program flow (`main.cc`)
 //
+// [[_TOC_]]
 //
 // This file contains the main program flow. In this example, we solve a single-phase flow problem
 // to obtain a pressure distribution in the domain. Subsequently, the distribution of volume fluxes
 // is computed from that pressure distribution, which is then passed to a tracer problem to solve
 // the transport of an initial contamination through the model domain.
-// ### Included header files
+// ## Included header files
 // <details>
 // [[exclude]]
 // Some generic includes.
@@ -66,7 +67,7 @@
 // </details>
 //
 
-// ### The main function
+// ## The main function
 // We will now discuss the main program flow implemented within the `main` function.
 // At the beginning of each program using Dune, an instance of `Dune::MPIHelper` has to
 // be created. Moreover, we parse the run-time arguments from the command line and the