Jeff D. Hamann <jeff.hamann@forestinformatics.com> and
Arne Henningsen <ahenningsen@agric-econ.uni-kiel.de>
This package contains functions for fitting simultaneous
systems of linear and nonlinear equations using Ordinary Least
Squares (OLS), Weighted Least Squares (WLS), Seemingly Unrelated
Regressions (SUR), Two-Stage Least Squares (2SLS), Weighted
Two-Stage Least Squares (W2SLS), Three-Stage Least Squares (3SLS),
and Weighted Three-Stage Least Squares (W3SLS).