1. Charis Elizabeth Idicheria, Alexander Schellong, Jobst Fiedler, Matthias Kammer, Marie-Therese Huppertz, Horst Westerfeld, A review of 311 in New York City.
2. NYC open data, https://nycopendata.socrata.com/Social-Services/311-Service-Requests-from-2010-to-Present/erm2-nwe9.
3. Sam Goodgame, David Harding, Romulo Manzano, NYC open data crunched & visualized, http://people.ischool.berkeley.edu/ samuel.goodgame/311/#daily.
4. Kansas City open data, https://data.kcmo.org/311/311-Call-Center-Service-Requests/7at3-sxhp/data.
5. Baltimore open data, https://data.baltimorecity.gov/City-Services/311-Customer-Service-Requests/9agw-sxsr/data.