References

-Wickham, Hadley and Garrett Grolemund. 2017. R for Data Science. O'Reilly.

-Healy, Kieran. 2019. Data Visualization A Practical Introduction. Princeton University Press.

-Wickham, Hadley. 2016. ggplot2 Elegant Graphics for Data Analysis. Springer. Second Edition.

-https://r-graphics.org/

-https://opr.princeton.edu/workshops/Downloads/2015Jan_ggplot2Koffman.pdf

-https://ggplot2-book.org/

-http://statseducation.com/Introduction-to-R/modules/graphics/ggplot2/

-https://dokumen.pub/qdownload/data-visualization-a-practical-introduction-0691181616-9780691181615.html