Field, Andy, Jeremy Miles, and Zoë Field. 2012. Discovering Statistics Using r. Sage publications.
Grolemund, Garrett, and Hadley Wickham. 2011. “Dates and Times Made Easy with lubridate.” Journal of Statistical Software 40 (3): 1–25.
R Core Team. 2021. R: A Language and Environment for Statistical Computing. Vienna, Austria: R Foundation for Statistical Computing.
Wickham, Hadley. 2009. Ggplot2: Elegant Graphics for Data Analysis. Springer-Verlag New York.
———. 2017. Tidyverse: Easily Install and Load the ’Tidyverse’.
Wickham, Hadley, Romain Francois, Lionel Henry, and Kirill Müller. 2017. Dplyr: A Grammar of Data Manipulation.
Wickham, Hadley, and Lionel Henry. 2018. Tidyr: Easily Tidy Data with ’Spread()’ and ’Gather()’ Functions.
Wickham, Hadley, Jim Hester, and Romain Francois. 2017. Readr: Read Rectangular Text Data.