Varela Juárez, Ricardo, Tomás Cuevas Contreras, and Sergio Salmerón Manzanares. 2021. “Effects of the Tip on the Socio-Economy and the Human”. Noesis. Journal of Social Sciences and Humanities 24 (47-1):49-68. https://doi.org/10.20983/noesis.2015.12.4.