diff --git a/_bookdown.yml b/_bookdown.yml
index 1295a8b..357281f 100644
--- a/_bookdown.yml
+++ b/_bookdown.yml
@@ -2,4 +2,4 @@ book_filename: "dataviz"
 delete_merged_file: true
 language:
   ui:
-    chapter_name: "Chaptire "
+    chapter_name: "Chapitre "
diff --git a/_output.yml b/_output.yml
index d1f9e85..d77390e 100644
--- a/_output.yml
+++ b/_output.yml
@@ -7,11 +7,3 @@ bookdown::gitbook:
       after: |
         <li><a href="https://github.com/rstudio/bookdown" target="blank">Published with bookdown</a></li>
     download: ["pdf", "epub"]
-bookdown::pdf_book:
-  includes:
-    in_header: preamble.tex
-  latex_engine: xelatex
-  citation_package: natbib
-  keep_tex: yes
-bookdown::epub_book: default
-
diff --git a/packages.bib b/packages.bib
index 781adb4..44edfed 100644
--- a/packages.bib
+++ b/packages.bib
@@ -6,20 +6,6 @@
   year = {2018},
   url = {https://www.R-project.org/},
 }
-@Manual{R-dplyr,
-  title = {dplyr: A Grammar of Data Manipulation},
-  author = {Hadley Wickham and Romain François and Lionel Henry and Kirill Müller},
-  year = {2019},
-  note = {R package version 0.8.0.1},
-  url = {https://CRAN.R-project.org/package=dplyr},
-}
-@Manual{R-forcats,
-  title = {forcats: Tools for Working with Categorical Variables (Factors)},
-  author = {Hadley Wickham},
-  year = {2018},
-  note = {R package version 0.3.0},
-  url = {https://CRAN.R-project.org/package=forcats},
-}
 @Manual{R-ggplot2,
   title = {ggplot2: Create Elegant Data Visualisations Using the Grammar of Graphics},
   author = {Hadley Wickham and Winston Chang and Lionel Henry and Thomas Lin Pedersen and Kohske Takahashi and Claus Wilke and Kara Woo},
@@ -27,27 +13,6 @@
   note = {R package version 3.1.1},
   url = {https://CRAN.R-project.org/package=ggplot2},
 }
-@Manual{R-patchwork,
-  title = {patchwork: The Composer of ggplots},
-  author = {Thomas Lin Pedersen},
-  year = {2017},
-  note = {R package version 0.0.1},
-  url = {https://github.com/thomasp85/patchwork},
-}
-@Manual{R-purrr,
-  title = {purrr: Functional Programming Tools},
-  author = {Lionel Henry and Hadley Wickham},
-  year = {2019},
-  note = {R package version 0.3.2},
-  url = {https://CRAN.R-project.org/package=purrr},
-}
-@Manual{R-readr,
-  title = {readr: Read Rectangular Text Data},
-  author = {Hadley Wickham and Jim Hester and Romain Francois},
-  year = {2018},
-  note = {R package version 1.3.1},
-  url = {https://CRAN.R-project.org/package=readr},
-}
 @Manual{R-see,
   title = {see: Visualisation Toolbox for 'easystats' and Extra Geoms, Themes
 and Color Palettes for 'ggplot2'},
@@ -56,27 +21,6 @@ and Color Palettes for 'ggplot2'},
   note = {R package version 0.1.0},
   url = {https://CRAN.R-project.org/package=see},
 }
-@Manual{R-stringr,
-  title = {stringr: Simple, Consistent Wrappers for Common String Operations},
-  author = {Hadley Wickham},
-  year = {2019},
-  note = {R package version 1.4.0},
-  url = {https://CRAN.R-project.org/package=stringr},
-}
-@Manual{R-tibble,
-  title = {tibble: Simple Data Frames},
-  author = {Kirill Müller and Hadley Wickham},
-  year = {2019},
-  note = {R package version 2.1.1},
-  url = {https://CRAN.R-project.org/package=tibble},
-}
-@Manual{R-tidyr,
-  title = {tidyr: Easily Tidy Data with 'spread()' and 'gather()' Functions},
-  author = {Hadley Wickham and Lionel Henry},
-  year = {2019},
-  note = {R package version 0.8.3},
-  url = {https://CRAN.R-project.org/package=tidyr},
-}
 @Manual{R-tidyverse,
   title = {tidyverse: Easily Install and Load the 'Tidyverse'},
   author = {Hadley Wickham},