Alam, Muhammad Jawaherul, Md. Abul Hassan Samee, Mashfiqui Rabbi, and Md. Saidur Rahman. “Minimum-Layer Upward Drawings of Trees”. Journal of Graph Algorithms and Applications 14, no. 2 (January 1, 2010): 245–267. Accessed July 6, 2024. http://jgaa-v4.cs.brown.edu/index.php/jgaa/article/view/paper206.