Classical growth convergence regressions fail to account for various sources of heterogeneity and nonlinearity. While recent contributions are able to address either the one or the other, we present a simple two-step method to address both issues. Based on a slightly augmented version of a...

In this paper we reconsider the results in Wang [Wang, J., 1995. Asymptotic normality of L1-estimators in nonlinear regression. J. Multivariate Anal. 54, 227-238; Wang, J., 1996. Asymptotics of least-squares estimators for constrained nonlinear regression. Ann. Statist. 4, 1316-1326], who studies...