Team S. Characterization of Digraphs of Right (Left) Zero Unions of Groups: Sr. Arworn, U. Knauer, N. Na Chiangmai. Thai J Math [Internet]. 2003 Jun. 1 [cited 2024 May 2];1(1):131-40. Available from: https://thaijmath2.in.cmu.ac.th/index.php/thaijmath/article/view/15