The research should be made using the sources below.
Foster, B. (Producer) & Gibney, A. (Director). (2012) Park Avenue: Money, Power & the American Dream [Video File]. Retrieved from https://to.pbs.org/2lxb3lu
Belchamber, G. (1996). Disappearing middle class or vanishing bottom? A comment on Gregory. The Economic Record, 72(218), 287-293. Retrieved from https://bit.ly/2QPtWxy
Posadas, J. (2016). Theological complicity in the disappearing of the working class. Dialog: A Journal of Theology, 55(1), 70-78. Retrieved from https://bit.ly/2Abhq60
Watson, P. (2018, March 8). The middle class might nearly disappear in the next decade. Forbes. Retrieved from https://bit.ly/2pUZJly
Ehrig, J. (2003). The disappearance of the American middle class (Doctoral dissertation, Lehigh University, Bethlehem, Pennsylvania). Retrieved from https://bit.ly/2CjFViP