Hi Paul, I would like to incorporate the numeric and Trott & Palmer R1rho models from your code in the sim_all.tar file. But for this to be legally possible, you need to release your code under an appropriate licence. You permanently own the copyright on this Matlab code but, for it to be used in relax, you must say that you release the code under the GPLv3+ licence. And you need to give the years you developed the code. You could do this by responding to this email, making sure it goes to the mailing list. An email to a archived public mailing list is a sufficient legal instrument. You need to say that you are willing to licence the contents of the sim_all.tar file (located at https://gna.org/support/download.php?file_id=18404) and attached to the task https://gna.org/task/?7712 under the GNU General Public Licence, version three or higher. You must also give the dates that your copyrights are for. I can see that the date on all files is 2005, but you may have started this a few years before that date. You can copy and paste some of this message for your email. Cheers, Edward