diff --git a/examples/1ptracer/README.md b/examples/1ptracer/README.md
index c85a34d1ec12377864996dd3c72ef8132a504b3c..b0cd88f3bd4b2e779e53dea453af5c29b6ce3a69 100644
--- a/examples/1ptracer/README.md
+++ b/examples/1ptracer/README.md
@@ -39,7 +39,7 @@ The transport of the contaminant component $`\kappa`$ is based on the previously
 
 where $`X^\kappa`$ is the mass fraction of the contaminant component $`\kappa`$ and $` D^\kappa_\text{pm} `$ is the effective diffusivity.
 
-The effective diffusivity is a function of the diffusion coefficient of the component $`D^\kappa`$ and the porosity and tortuosity $`\tau`$ of the porous medium:
+The effective diffusivity is a function of the diffusion coefficient of the component $`D^\kappa`$ and the porosity and tortuosity $`\tau`$ of the porous medium (see [dumux/material/fluidmatrixinteractions/diffusivityconstanttortuosity.hh](https://git.iws.uni-stuttgart.de/dumux-repositories/dumux/-/blob/master/dumux/material/fluidmatrixinteractions/diffusivityconstanttortuosity.hh)):
 
 ```math
 D^\kappa_\text{pm}= \phi \tau D^\kappa.
diff --git a/examples/1ptracer/doc/intro.md b/examples/1ptracer/doc/intro.md
index 22461959bc7bf716fdebbb0a95236dd46fdf7a7b..fa0964231f6159d1d67e04457135f1b2859621ae 100644
--- a/examples/1ptracer/doc/intro.md
+++ b/examples/1ptracer/doc/intro.md
@@ -39,7 +39,7 @@ The transport of the contaminant component $`\kappa`$ is based on the previously
 
 where $`X^\kappa`$ is the mass fraction of the contaminant component $`\kappa`$ and $` D^\kappa_\text{pm} `$ is the effective diffusivity.
 
-The effective diffusivity is a function of the diffusion coefficient of the component $`D^\kappa`$ and the porosity and tortuosity $`\tau`$ of the porous medium:
+The effective diffusivity is a function of the diffusion coefficient of the component $`D^\kappa`$ and the porosity and tortuosity $`\tau`$ of the porous medium (see [dumux/material/fluidmatrixinteractions/diffusivityconstanttortuosity.hh](https://git.iws.uni-stuttgart.de/dumux-repositories/dumux/-/blob/master/dumux/material/fluidmatrixinteractions/diffusivityconstanttortuosity.hh)):
 
 ```math
 D^\kappa_\text{pm}= \phi \tau D^\kappa.