diff --git a/book/_config.yml b/book/_config.yml
index 1e9576f..7dde32f 100644
--- a/book/_config.yml
+++ b/book/_config.yml
@@ -4,7 +4,7 @@ author: TeachBooks Team, built with <a href="https://teachbooks.io">TeachBooks</
                                                      # Replace TeachBooks Teams with your own name in the line above, configuratin part of JupyterBook: https://jupyterbook.org/en/stable/customize/config.html
 execute:
   execute_notebooks: "off"                           # Replace this if you want don't have notebooks with output and you want to add notebook output during build, configuration part of Jupyter Book (https://jupyterbook.org/en/stable/customize/config.html)
-  cache:             `_build/.jupyter_cache/`        # Default value (line can be removed), sets path to the jupyter cache that will be used to store execution artifacts, doesn't work in GitHub workflow, configuration part of Jupyter Book (https://jupyterbook.org/en/stable/customize/config.html)
+  cache:             "_build/.jupyter_cache/"        # Default value (line can be removed), sets path to the jupyter cache that will be used to store execution artifacts, doesn't work in GitHub workflow, configuration part of Jupyter Book (https://jupyterbook.org/en/stable/customize/config.html)
   exclude_patterns:  []                              # Default value (line can be removed), sets a list of patterns to *skip* in execution, configuration part of Jupyter Book (https://jupyterbook.org/en/stable/customize/config.html), can overwritten by Sphinx-NB-Execution-Patterns (https://teachbooks.io/manual/_git/github.com_TeachBooks_Sphinx-NB-Execution-Patterns/Manual/README.html)
   timeout:           30                              # Default value (line can be removed), sets he maximum time (in seconds) each notebook cell is allowed to run, configuration part of Jupyter Book (https://jupyterbook.org/en/stable/customize/config.html)
   run_in_temp:       false                           # Default value (line can be removed), disables a temporary directory was the command working directory (cwd), configuration part Jupyter Book (https://jupyterbook.org/en/stable/customize/config.html)