Xin, Xiao Long, Rajab Ali Borzooei, and Young Bae Jun. “Positive Implicative Soju Ideals in BCK-Algebras”. Bulletin of the Section of Logic 48, no. 1 (March 30, 2019): 1–18. Accessed April 29, 2024. https://czasopisma.uni.lodz.pl/bulletin/article/view/5381.