Liprandi-Cortes, N., del Castillo-Mussot, M., & Soriano-Hernández, P. G. (2022). Two-class structure of Forbes Global 2000 firms sales per employee similar to countries income distributions including some COVID-19 pandemic effects. Revista Mexicana De Física, 68(4 Jul-Aug), 041402 1–. https://doi.org/10.31349/RevMexFis.68.041402