I just watched the Laurence Tribe interview. Holy crap. Laurence Tribe just said that his former law student, Ted Cruz was wrong in stating that the issue is settled.
http://www.msnbc.com/the-last-word/watch/trump-gives-cruz-legal-advice-on-citizenship-598149699969
Here is a link to a 2005 Boston Law Review article that covers the topic...this is authoritative survey of law on the matter according to Laurence Tribe due to its in depth research...it is 100 pages in length, stating the issue is not settled.
Here