Update free-R-programming-books-langs.md (#8387)

* Update free-programming-books-langs.md

* Update free-programming-books-langs.md

* Update books/free-programming-books-langs.md

Co-authored-by: Eric Hellman <eric@hellman.net>

* Update books/free-programming-books-langs.md

Co-authored-by: Eric Hellman <eric@hellman.net>

Co-authored-by: Eric Hellman <eric@hellman.net>

books/free-programming-books-langs.md

@@ -2054,8 +2054,10 @@ That section got so big, we decided to split it into its own file, the [BY SUBJE
 ### R
 
 * [Advanced R Programming](http://adv-r.had.co.nz) - Hadley Wickham
+* [An Introduction to ggplot2](https://bookdown.org/ozancanozdemir/introduction-to-ggplot2) - Ozancan Ozdemir
 * [An Introduction to R](https://cran.r-project.org/doc/manuals/R-intro.html) - David M. Smith, William N. Venables
 * [An Introduction to Statistical Learning with Applications in R](https://web.stanford.edu/~hastie/ISLR2/ISLRv2_website.pdf) - Gareth James, Daniela Witten, Trevor Hastie, Robert Tibshirani (PDF)
+* [Beyond Multiple Linear Regression](https://bookdown.org/roback/bookdown-BeyondMLR) - Paul Roback, Julie Legler
 * [blogdown: Creating Websites with R Markdown](https://bookdown.org/yihui/blogdown/) - Yihui Xie, Amber Thomas, Alison Presmanes Hill
 * [Cookbook for R](http://www.cookbook-r.com) - Winston Chang
 * [Data Analysis and Prediction Algorithms with R](https://rafalab.github.io/dsbook/) - Rafael A. Irizarry
@@ -2077,6 +2079,7 @@ That section got so big, we decided to split it into its own file, the [BY SUBJE
 * [R Programming](https://en.wikibooks.org/wiki/R_Programming) - Wikibooks
 * [R Programming for Data Science](https://bookdown.org/rdpeng/rprogdatascience/) - Roger D. Peng 
 * [R Succinctly, Syncfusion](https://www.syncfusion.com/resources/techportal/ebooks/rsuccinctly) (PDF, Kindle) (email address *requested*, not required)
+* [Statistical Inference via Data Science](https://moderndive.com) - Chester Ismay, Albert Y. Kim
 * [Summary and Analysis of Extension Program Evaluation in R](https://rcompanion.org/handbook/index.html) - Salvatore S. Mangiafico
 * [The caret Package](http://topepo.github.io/caret/index.html) - Max Kuhn
 * [The R Inferno](http://www.burns-stat.com/pages/Tutor/R_inferno.pdf) - Patrick Burns (PDF)