By Jacobson, Jodi L..
Washington, D.C. Worldwatch Institute 1987 .
54 p. 22 cm..
091646881X (pbk.)

By Postel, Sandra..
Washington, D.C. Worldwatch Institute 1988 .
66 p. 22 cm..
0916468844 (pbk.)

By Flavin, Christopher..
Washington, D.C. Worldwatch Institute 1988 .
74 p. 22 cm..
0916468836 (pbk.)

By Weber, Peter.
Washington, DC Worldwatch Institute 1993 .
66 p. 22 cm..
1878071165 (pbk.)

By French, Hilary F..
Washington, DC Worldwatch Institute 1993 .
74 p. , "March, 1993." 22 cm..
1878071149

By Renner, Michael.
Washington, DC Worldwatch Institute 1993 .
74 p. , "May 1993." 22 cm..
1878071157