Anyikwa, I. et al. 2021. The Persistence of Suicides in G20 Countries between 1990 and 2017: an SPSM Approach to Three Generations of Unit Root Tests. Comparative Economic Research. Central and Eastern Europe. 24, 2 (Jun. 2021), 153–173. DOI:https://doi.org/10.18778/1508-2008.24.17.