“I'm not Stubborn; I'm right!”

The phrase has been used commonly for several decades, and there may be earlier sources. In a 1992 Business North Carolina article, Dooley noted about being an NFL referee that "If you're wrong, everybody in the world will tell you. If you're right, nobody cares. I'm not always right, but I'm never in doubt." Cf. the Free Library article http://www.thefreelibrary.com/Sundays,+he+turns+foul-mouthed.-a011823168.
Attributed

Message to linux-kernel mailing list, 2005-07-14, Torvalds, Linus, 2006-08-28 http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg83284.html,
2000s, 2005

Responding to audience question, "Are you left-wing or right-wing?"
Unidentified press conference, 1968
Featured in Pat Paulsen for President (1968), part 3 of 6 http://www.youtube.com/watch?v=LdjY3TXYJkw&feature=relmfu, 02:49 ff (20:49 ff in full program)

Said during his exile in Peking, as quoted by Oriana Fallaci (June 1973), Intervista con la Storia (sixth edition, 2011).
Interviews

Source: Into the Woods

Source: Brave New World

Wesley Hayden and Gail Hayden.
Montana 1948

Source: Catching Fire

As quoted in "Whoopi Goldberg, A One-Woman Character Parade" https://www.newspapers.com/image/?clipping_id=68252476 by Michael Kuchwara, AP Drama Writer, The Fremont News-Messenger (November 29, 1984), p. 31.