When this film first came out, there were a number of reviews which
mentioned the Mark Twain influence. Director Jeff Nichols acknowledge
Twain's influence on his work in at least one interview and a number
of media outlets picked up on it.  One such story still currently
online is from The Guardian of May 2, 2013 at:

http://www.theguardian.com/film/2013/may/02/mud-director-jeff-nichols-twain