Cao, Son Thanh, and Linh Anh Nguyen. “Incorporating Stratified Negation into Query-Subquery Nets for Evaluating Queries to Stratified Deductive Databases”. COMPUTING AND INFORMATICS 38, no. 1 (April 26, 2019): 19–56. Accessed April 23, 2024. https://www.cai.sk/ojs/index.php/cai/article/view/2019_1_19.