Hi N Gauthier,
Again, I apologize for any inconvenience.
American Ancestors is published by the New England Historic Genealogical Society (NEHGS). It is a paid subscription and can be accessed online with NEHGS membership. I receive my magazine by mail. I cannot rightfully access the article online and make it available as a link, nor can I scan the article and make it available free to the public as it would not be ethical.
I felt that both of the articles I cited from this quarterly magazine (the other article is about the Abraham Lincoln/Robert E. Lee DNA study) would be of interest to various Wikitreers. I did list the citations for both articles as they can be accessed at any local Family History Center. Some Family History Centers are opened on a limited basis now, and more will be opening as of April 2021 as the pandemic curve bends downward. I wanted to alert our Wikitree family as a courtesy based on any interest in these topics.
As mentioned at the top, here is the citation for the article and, hopefully, you will be able to obtain this at your local Family History Center, or perhaps a friend can make their NEHGS access available to you:
Bannerman, Alexander and Roberts, Gary Boyd. An Ancestor Table, as Currently Known, of President Joseph Robinette Biden, Jr. Boston, MA: American Ancestors, Vol. 21, No. 4., Winter 2021. Pages 28-31.