I. F. Grant y Sear, C.,
Decision tools for sustainable development. Chatham, UK: Natural Resources Institute, University of Greenwich, 1999, p. v, 267 p. : fig., tab.
L. Segnestam,
«Environmental performance indicators : a second edition note», vol. no. 71. World Bank Environment Department, Washington, DC, USA, p. ix, 38 p. : boxes, fig., 1999.
UN-HABITAT -Nairobi, KE, United Nations Human Settlements Programme y Nairobi, K. E. U. N. E. P. -,
«Preparing the SCP environmental profile», vol. vol. 1. UN-Habitat, United Nations Centre for Human Settlements, Nairobi, Kenya, p. vi, 109 p., 1999.