Lukovsky, I. O., et al. “International Conference ‘INAMTAP’96 (Computer Science, Computational and Applied Mathematics: Theory, Application, and Prospects)’”. Ukrains’kyi Matematychnyi Zhurnal, vol. 49, no. 4, Apr. 1997, pp. 611–612, https://umj.imath.kiev.ua/index.php/umj/article/view/5040.