Markosyan, S. E. and Khachaturyan, A. H. (2009) “OPTIMAL LEVEL PLACEMENT OF THE TRANSITIVE ORIENTED AND BIPARTITE ORIENTED GRAPHS BY HEIGHT”, Proceedings of the YSU A: Physical and Mathematical Sciences. Yerevan, Armenia, 43(2 (219), pp. 43–49. doi: 10.46991/PYSU:A/2009.43.2.043.