Mel’nichenko, I. P., and S. A. Plaksa. 1997. “Potential Fields With Axial Symmetry and Algebras of Monogenic Functions of Vector Variables. III”. Ukrains’kyi Matematychnyi Zhurnal 49 (2), 228–243. https://umj.imath.kiev.ua/index.php/umj/article/view/5000.