Appleton, J. D., Williams, T. M., Orbea, H., & Carrasco, M. (2001). Fluvial Contamination Associated with Artisanal Gold Mining in the Ponce Enríquez, Portovelo-Zaruma and Nambija Areas, Ecuador. Water, Air & Soil Pollution, 131(1-4), 19. https://doi.org/10.1023/A:1011965430757
Chicago Style (17th ed.) CitationAppleton, J. D., T. M. Williams, H. Orbea, and M. Carrasco. "Fluvial Contamination Associated with Artisanal Gold Mining in the Ponce Enríquez, Portovelo-Zaruma and Nambija Areas, Ecuador." Water, Air & Soil Pollution 131, no. 1-4 (2001): 19. https://doi.org/10.1023/A:1011965430757.
MLA (9th ed.) CitationAppleton, J. D., et al. "Fluvial Contamination Associated with Artisanal Gold Mining in the Ponce Enríquez, Portovelo-Zaruma and Nambija Areas, Ecuador." Water, Air & Soil Pollution, vol. 131, no. 1-4, 2001, p. 19, https://doi.org/10.1023/A:1011965430757.