MacLean, L.C.W., T.J. Pray, T.C. Onstott, E.L. Brodie, T.C. Hazen, and G. Southam. 2007. “Mineralogical, Chemical and Biological Characterization of an Anaerobic Biofilm Collected from a Borehole in a Deep Gold Mine in South Africa”. Geomicrobiology Journal 24: 491-504. doi:10.1080/01490450701572416.