L. Liu and I. Ruiz, “Convergence Hypothesis: Evidence from Panel Unit Root Test with Spatial Dependence”, ecos.econ., vol. 10, no. 23, pp. 37–56, Oct. 2006, Accessed: Nov. 11, 2026. Available: https://publicaciones.eafit.edu.co/index.php/ecos-economia/article/view/1979