Murthy, Vasudeva, and Albert Okunade. “Is the Health Care Price Inflation in US Urban Areas Stationary? Evidence from Panel Unit Root Tests”. Journal of Economics, Finance and Administrative Science 23, no. 44 (June 1, 2018): 77–94. Accessed August 20, 2022. https://revistas.esan.edu.pe/index.php/jefas/article/view/113.