L. Ghost work : how to stop Silicon Valley from building a new global underclass. Boston. : 51. ISBN 978-1-328-56628-7 (英语). 使用|accessdate=需要含有|url= (帮助)
L. Ghost work : how to stop Silicon Valley from building a new global underclass. Boston. : 53. ISBN 978-1-328-56628-7 (英语). 使用|accessdate=需要含有|url= (帮助)
Hagedorn, John M., and Perry Macon. People and Folks: Gangs, Crime and the Underclass in a Rustbelt City. Lake View Press, Chicago, IL, (paperback: ISBN 0-941702-21-9;