Atto, Muhsin. “Graph Inclusion and Matching Algorithms for Programs Manipulating Singly Linked Heaps”. Science Journal of University of Zakho 9, no. 1 (March 30, 2021): 30-37. Accessed April 20, 2021. https://sjuoz.uoz.edu.krd/index.php/sjuoz/article/view/778.