K. Ludi: consumption behaviour in Zambia 19
and Agricultural Statistics in Africa in Support of Food Security and Poverty
Reduction Policies and Programmes, Pretoria.
Phillips PCB and Perron P. 1988. Testing for a unit root in time series regression.
Biometrika, 75:335-578.
The World Bank. 2004. World Development Indicators. Extracted from Time Series
Explorer.