Kandil, Kandil, O. A. E. Tantawy, S. A. El-Sheikh, and Shawqi. A. Hazza. 2017. “On Pairwise ?-Open Soft Sets and Pairwise Locally Closed Soft Sets”. American Scientific Research Journal for Engineering, Technology, and Sciences 28 (1):225-47. https://asrjetsjournal.org/index.php/American_Scientific_Journal/article/view/2676.