1. Sorting inc logn parallel steps
2. D. E. Knuth, The Art of Computer Programming: Volume 3: Sorting and Searching, 2nd edn. (Addison-Wesley Longman, USA, 1998) pp. 225–228.
3. K. H. Rosen, Discrete Mathematics and its Applications, 5th edn. (McGraw-Hill Companies, USA, 2003) pp. 520–525.