Mel'nichenko, I. P., and S. A. Plaksa. “Potential Fields With Axial Symmetry and Algebras of Monogenic Functions of a Vector Variable. I”. Ukrains’kyi Matematychnyi Zhurnal, vol. 48, no. 11, Nov. 1996, pp. 1518-29, https://umj.imath.kiev.ua/index.php/umj/article/view/5206.