@misc{CCR180032019,
  title = {Calendar operator practices — Guidelines to protect against calendar abuse},
  author = {GmbH, Thomas Schäfer, 1&1 Mail&Media Development and Technology and Wisconsin-Madison, Jesse Thompson, University of and CalConnect and CalConnect},
  howpublished = {CC/R 18003:2019},
  year = {2019},
  edition = {1},
  publisher = {CalConnect},
}