1. Adams, S., Titusa, R., Pietersen, K., Tredoux, G., & Harris, C. (2001). Hydrochemical characteristics of aquifers near Sutherland in the Western Karoo. South African Journal of Hydrology, 241, 91–103.
2. Aiuppa, A., Allard, P., D’Alessandro, W., Michel, A., Parello, F., Treuil, M., et al. (2000). Mobility and fluxes of major, minor and trace elements during basalt weathering and groundwater transport at Mt Etna volcano (Sicily). Geochimica et Cosmochimica Acta, 64, 1827–1841.
3. Aiuppa, A., Bellomo, S., Brusca, L., D’Alessandro, W., & Federico, W. C. (2003). Natural and anthropogenic factors affecting groundwater quality of an active volcano (Mt. Etna, Italy). Applied Geochemistry, 18, 863–882.
4. APHA, AWWA & WEF. (1998). Standard methods for the examination of water and wastewater. Washington, DC: American Public Health Association.
5. Appelo, C. A. J., & Postma, D. (1996). Chemical analysis of groundwater, geochemistry, groundwater and pollution. Rotterdam: Balkema.