C. Bartone, Bernstein, J. D., y Wright, F.,
«Investments in solid waste management : opportunities for environmental improvement», vol. WPS405. World Bank, Policy, Research and External Affairs Complex, Washington, DC, USA, p. v, 85 p.: 6 fig., 5 tab., 1990.
T. Katko, Hukka, J., y Seppala, O.,
«Kenya water sector : discussion paper». Tampere University of Technology, Institute of Water and Environmental Engineeri, Tampere, Finland, p. 95 p.: fig., tab., 1990.