@InProceedings{www20-paywalls,
  title =        "Keeping Out the Masses: Understanding the Popularity
                 and Implications of Internet Paywalls",
  author =       "Panagiotis Papadopoulos and Peter Snyder and Benjamin
                 Livshits",
  year =         "2020",
  month =        may,
  booktitle =    "International World Wide Web Conference {(WWW)}",
}