diff --git a/docs/_source/changelog.rst b/docs/_source/changelog.rst
index 2b0ff367fc2e75ef02d540d7888f390d8aad18c2..76a914d9fde440113969c11714909606e569de0b 100644
--- a/docs/_source/changelog.rst
+++ b/docs/_source/changelog.rst
@@ -1,4 +1,4 @@
 Changelog
 =========
 
-.. include:: ../../CHANGELOG.md
\ No newline at end of file
+.. mdinclude:: ../../CHANGELOG.md
\ No newline at end of file
diff --git a/docs/_source/conf.py b/docs/_source/conf.py
index d4c71e69cc38499930d28952562372106b5f13b3..c293f0b46f5c65ceda5aa2c54c3cbb343a4e6663 100644
--- a/docs/_source/conf.py
+++ b/docs/_source/conf.py
@@ -46,9 +46,10 @@ extensions = [
     'sphinx.ext.napoleon',
     'sphinx_rtd_theme',
     'sphinx.ext.githubpages',
-    'recommonmark',
+    #'recommonmark',
     'sphinx.ext.autosectionlabel',
     'sphinx_autodoc_typehints',  # must be loaded after napoleon
+    'm2r2'
 ]
 
 # 2020-02-19 Begin
diff --git a/docs/requirements_docs.txt b/docs/requirements_docs.txt
index a1294e314d9d04402ba7c063754a56b49deab602..a39acca8a7cf887237f595d7992960ac10233a85 100644
--- a/docs/requirements_docs.txt
+++ b/docs/requirements_docs.txt
@@ -2,4 +2,5 @@ sphinx==3.0.3
 sphinx-autoapi==1.3.0
 sphinx-autodoc-typehints==1.10.3
 sphinx-rtd-theme==0.4.3
-recommonmark==0.6.0
\ No newline at end of file
+#recommonmark==0.6.0
+m2r2==0.2.5
\ No newline at end of file
diff --git a/mlair/data_handler/station_preparation.py b/mlair/data_handler/station_preparation.py
index 6112e7c5dd937c9b3217d67037d7ad229e8eb963..f3428e91bae3dc1d94a45dd7ff2bf931cff1fa54 100644
--- a/mlair/data_handler/station_preparation.py
+++ b/mlair/data_handler/station_preparation.py
@@ -76,7 +76,7 @@ class DataHandlerSingleStation(AbstractDataHandler):
         # internal
         self.data = None
         self.meta = None
-        self.variables = statistics_per_var.keys() if variables is None else variables
+        self.variables = list(statistics_per_var.keys()) if variables is None else variables
         self.history = None
         self.label = None
         self.observation = None