R documentation

R Programming

• R for Data Science, by Grolemund and Wickham
  
• Advanced R, by Hadley Wickham

R Markdown

• Introduction to R Markdown
  
• R Markdown from R Studio
  
• R Markown Cheat Sheet
  
• R Markdown: The Definitive Guide, by Xie, Allaire and Grolemund
  
• Pimp my RMD: a few tips for R Markdown, by Yan Holtz

R Packages

• R Packages, by Hadley Wickham

R Websites

• Creating websites in R, by Emily C. Zabor
  
• Chapter 10: Websites in “R Markdown: The Definitive Guide”

R, Git and GitHub

• Happy Git and GitHub for the useR, by Jenny Bryan and Jim Hester
  
• “Git and GitHub” chapter in “R packages”

R, C and C++

• “Rewriting R code in C++” chapter in “Advanced R”