@techreport{murrell-pedersen-skintzos-compositing-2023,
  title="Porter-Duff Compositing Operators in R Graphics",
  author = {Paul Murrell and Thomas Lin Pedersen and Panagiotis Skintzos},
  year={2023},
  note={version 1},
  institution={Department of Statistics, The University of Auckland},
  number={2023-02},
  url={https://stattech.blogs.auckland.ac.nz/2023/05/22/2023-02-porter-duff-compositing-operators-in-r-graphics},
  doi={10.17608/k6.auckland.23034641}
}