In the Licensing page (in the Software Projects chapter). From the ggplot website:
@Book{,
author = {Hadley Wickham},
title = {ggplot2: Elegant Graphics for Data Analysis},
publisher = {Springer-Verlag New York},
year = {2016},
isbn = {978-3-319-24277-4},
url = {https://ggplot2.tidyverse.org},
}
In the Licensing page (in the Software Projects chapter). From the ggplot website: