http://www.seas.upenn.edu/~cis552/lectures/RedBlackGADT1.html http://www.seas.upenn.edu/~cis552/lectures/RedBlackGADT1.htm... Red-black trees via GADTs, courte

http://www.seas.upenn.edu/~cis552/lectures/RedBlackGADT1.html http://www.seas.upenn.edu/~cis552/lectures/RedBlackGADT1.htm... Red-black trees via GADTs, courtesy of Penn's CIS 552 course.