how many unit root does it need what is unit root what is the unit root on a gmm model? what is the unit root of gmm how to compute units in gmm what is unit roots in the gmm what is rho in gmm unit root for gmm what is unit root how to find the unit root in a panel model define unit root and unit test what is unit root what is unit root for gmm what is unit root in gmm estimation what is rho in gmm gmm unit root test when using unit root estimation gmm, how to estimate the gamma t how to find if rho is unit root what is rho? what is the unit root for gmm