Kamaku W, Mutembei J, Kivunge B. Positive P 0,1 Matrix Completion Problem for Order Four Digraphs with Zero, One, Two and Three Arcs. IJSBAR. 2017;34(3):22-30. Accessed September 10, 2025. https://www.gssrr.org/JournalOfBasicAndApplied/article/view/7671