1. Attiya, H., Welch, J.: Distributed Computing: Fundamentals, Simulations and Advanced Topics. McGraw-Hill, New York (1998)
2. Chu, Y., Liu, T.: On the shortest arborescence of a directed graph. Science Sinica 14, 1396–1400 (1965)
3. Lecture Notes in Computer Science;R. Cohen,2005
4. Cormen, T.H., Leiserson, C.E., Rivest, R.L.: Introduction to Algorithms. MIT Press/McGraw-Hill (1990)
5. Lecture Notes in Computer Science;A. Czumaj,1997