J.E. Cirlot(英語版), "City"; A Dictionary of Symbols, 2nd ed., translated from Spanish to English by Jack Read; New York: Philosophical Library, 1971; pp. 48–49 (online).
Engel, Jerome S.; Berbegal-Mirabent, Jasmina; Piqué, Josep M. (2018). “The renaissance of the city as a cluster of innovation”. Cogent Business & Management5 (1): 1532777. doi:10.1080/23311975.2018.1532777. hdl:10419/206125.
Voorn, Bart; van Genugten, Marieke L.; van Thiel, Sandra (2017-09-03). “The efficiency and effectiveness of municipally owned corporations: a systematic review”. Local Government Studies43 (5): 820–841. doi:10.1080/03003930.2017.1319360. hdl:2066/176125. ISSN0300-3930.
Engel, Jerome S.; Berbegal-Mirabent, Jasmina; Piqué, Josep M. (2018). “The renaissance of the city as a cluster of innovation”. Cogent Business & Management5 (1): 1532777. doi:10.1080/23311975.2018.1532777. hdl:10419/206125.
Voorn, Bart; van Genugten, Marieke L.; van Thiel, Sandra (2017-09-03). “The efficiency and effectiveness of municipally owned corporations: a systematic review”. Local Government Studies43 (5): 820–841. doi:10.1080/03003930.2017.1319360. hdl:2066/176125. ISSN0300-3930.
Robert L. Lineberry, "Mandating Urban Equality: The Distribution of Municipal Public Services"; in Hahn & Levine (1980). See: Hawkins v. Town of Shaw(英語版) (1971).
Joel A. Tarr(英語版), "The Evolution of the Urban Infrastructure in the Nineteenth and Twentieth Centuries"; in Hanson (1984).
J.E. Cirlot(英語版), "City"; A Dictionary of Symbols, 2nd ed., translated from Spanish to English by Jack Read; New York: Philosophical Library, 1971; pp. 48–49 (online).
Voorn, Bart; van Genugten, Marieke L.; van Thiel, Sandra (2017-09-03). “The efficiency and effectiveness of municipally owned corporations: a systematic review”. Local Government Studies43 (5): 820–841. doi:10.1080/03003930.2017.1319360. hdl:2066/176125. ISSN0300-3930.