Allen, C.C., Albert, F.G., Chafetz, H.S., Combie, J., Graham, C.R., Kieft, T.L., Kivett, S.J., McKay, D.S., Steele, A., Taunton, A.E., Taylor, M.R., Thomas-Keprta, K.L. and Westall, F. (2000) Microscopic Physical Biomarkers in Carbonate Hot Springs: Implications in the Search for Life on Mars. Icarus, 147, 49-67.