Talk:6-Isopropyl-6-nor-lysergic acid diethylamide

Hey guys, there is some statistics in this article that may not be backed up by the reference listed, but instead is quoted directly from David E. Nichols himself, in a personal email exchange i had with him. Screenshots are provided in the link (https://commons.wikimedia.org/wiki/File:IP-LADtalk.png). Is there any way I can cite this as a reference?