diff --git a/12_data_cleaning.rmd b/12_data_cleaning.rmd
index b6bc23f..b340368 100644
--- a/12_data_cleaning.rmd
+++ b/12_data_cleaning.rmd
@@ -25,7 +25,7 @@ Data scientists, by some accounts, spend 80% of their time cleaning data. Ensuri
 Marco Di Zio, Nadežda Fursova, et al., [Methodology for data validation 1.0](https://ec.europa.eu/eurostat/cros/system/files/methodology_for_data_validation_v1.0_rev-2016-06_final.pdf) (revised edition June 2016), Essnet Validat Foundation {PDF}
 
 
-## R Packages
+## Using R
 
 
 Mark van der Loo and Edwin de Jonge, _Statistical Data Cleaning with Applications in R_ [@Van_der_Loo_de_Jonge_2018]
@@ -33,9 +33,10 @@ Mark van der Loo and Edwin de Jonge, _Statistical Data Cleaning with Application
 
 Edwin de Jonge and Mark van der Loo, 2013, [An introduction to data cleaning with R](https://cran.r-project.org/doc/contrib/de_Jonge+van_der_Loo-Introduction_to_data_cleaning_with_R.pdf), Discussion Paper, Statistics Netherlands {PDF}
 
-Edwin de Jonge and Mark van der Loo, 2019, [Data Validation Infrastructure for R](https://arxiv.org/pdf/1912.09759.pdf), arXiv:1912.09759v1 {PDF}
 
+Samuel E. Buttrey, Lyn R. Whitaker, 2017, _A Data Scientist's Guide to Acquiring, Cleaning, and Managing Data in R_ [@Buttrey_Whitaker_2017]
 
+## R Packages
 
 
 ### `{validate}`
@@ -45,6 +46,9 @@ CRAN: [validate: Data Validation Infrastructure](https://cran.r-project.org/web/
 
 Vignette: [Introduction to Validate](https://cran.r-project.org/web/packages/validate/vignettes/introduction.html)
 
+Articles:
+
+* Edwin de Jonge and Mark van der Loo, 2019, [Data Validation Infrastructure for R](https://arxiv.org/pdf/1912.09759.pdf), arXiv:1912.09759v1 {PDF}
 
 
 -30-
diff --git a/book.bib b/book.bib
index c95ddf9..2ec923b 100644
--- a/book.bib
+++ b/book.bib
@@ -84,6 +84,16 @@ @article{Broman_Woo_2017
   }
 
 
+@Book{Buttrey_Whitaker_2017,
+  title = {A Data Scientist's Guide to Acquiring, Cleaning, and Managing Data in R},
+  author = {Samuel E. Buttrey and Lyn R. Whitaker},
+  publisher = {Wiley},
+  year = {2017},
+  isbn = {ISBN: 9781119080022},
+  url = {https://onlinelibrary.wiley.com/doi/book/10.1002/9781119080053},
+}
+
+
 
 @Book{Cairo_2013,
   title = {The Functional Art: An Introduction to Information Graphics and Visualization},
@@ -615,7 +625,7 @@ @Book{Van_der_Loo_de_Jonge_2018
   publisher = {Wiley},
   year = {2018},
   isbn = {ISBN: 978-1-118-89715-7},
-  url = {https://www.wiley.com/en-us/Statistical+Data+Cleaning+with+Applications+in+R-p-9781118897157},
+  url = {https://onlinelibrary.wiley.com/doi/book/10.1002/9781118897126},
 }