lnPC	= Natural log of yearly per capita wheat consumed;
ln%UR t	= Natural log of the share of urban population (%);
lnGDP t	= Natural log of the per capita GDP (US$);
lnDPR t	= Natural log of the domestically produced wheat in tons; and
lnIMP t	= Natural log of wheat imported (tons)
yd82	= Year>1981 dummy (yes=1)
k-1	= the lag length is reduced by 1
βi, αj, ϕj, γm, θn, ψ, τ, ω	= short-run dynamic coefficients of the model's adjustment toward long-term equilibrium
λ i	= speed of adjustment parameter with a negative sign;
ECTt−1	= the error correction term is the lagged value of the residuals obtained from the cointegration regression of the dependent variables on the regressors. Contains long-term information derived from the long-term cointegration relationship;
μ it	= the residuals (stochastic error term/ impulses or innovations or shocks.