López-Ruiz, M., Artazcoz, L., Martinez, J.M., Rojas, M., Benavides, F.G. (2015). Informal employment and health status in Central America. BMC Public Health, 15(698), 1-12.
https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-015-2030-9