Cacilda-André, Januário, and José Francisco Lastra-Rivero. 2019. “Socio-Environmental Implications of the Artisanal Exploitation of Aggregates in the Municipality of Sumbe, Cuanza Sul, Angola”. Boletín De Geología 41 (3):127-43. https://doi.org/10.18273/revbol.v41n3-2019006.