³Versions 4.0 through 5.0 of Matpower were distributed under version 3.0 of the GNU General Public License (GPL) [7] with an exception added to clarify our intention to allow Matpower to interface with Matlab as well as any other Matlab code or MEX-files a user may have installed, regardless of their licensing terms. The full text of the GPL can be found at https://www.gnu.org/licenses/gpl-3.0.txt. Matpower versions prior to version 4 had their own license.