New Scientist 1764, 25-29. Butler, R.W.H. 1991. The state of the Earth. New Scientist 1765, 50-51. Butler, R.W.H. 1992.
Technology defeats geology.
New Scientist 1807, 52. Butler, R.W.H. 1992. A picture of history. New Scientist 1811, 50. Butler, R.W.H. 1992.