World Charter for Nature 1982: Word 97, 40 kbytes.
Classic Essays: (in chronological order)
Leopold, Aldo (1948) The land ethic. In Leopold, A (1966) A sand county almanac, with other essays from Round River. Oxford University Press; New York. This collection of essays was in draft form when Leopold died in 1948. It was first published in 1949 under the title "A sand county almanac", by Ballantine, New York.
White: Historical roots of our ecological crisis. 1967
Hardin: Tragedy of the commons. 1968, Word 97, 60 kbytes.
Odum: Tyranny of small decisions. 1982, Word 97, 40 kbytes.
Ludwig et al. Uncertainty, resource exploitation, and conservation: lessons from history. 1993.
Steffen et al. Abrupt changes: the Achillies' Heels of the earth system. 2004, pdf from the April edition of Environment.