Изменения

* [http://en.wikipedia.org/wiki/Transitive_reduction Wikipedia: Transitive reduction]

* [http://archive.cs.uu.nl/pub/RUU/CS/techreps/CS-1987/1987-25.pdf J.A. La Poutré and J. van Leeuwen. «Maintenance of transitive closures and transitive reductions of graphs», 1987]