Opfergelt, S., Burton, K. W., Guicharnaud, R., Siebert, C., Gislason, S. R., & Halliday, A. N. (2011). Silicon isotopes in allophane as a proxy for mineral formation in volcanic soils. Applied Geochemistry, 26(S1), S115-S118. https://doi.org/10.1016/j.apgeochem.2011.03.044 (Original work published 2011)