Algebrodynamical Approach in Field Theory: Bisingular Solution and its   Modifications
  The criterion of differentiability of functions of quaternion variable is used as the basis of some algebraic field theory. Its necessary consequences are free Maxwell and Yang-Mills equations. The differentiability equations may be integrated in twistor variables and are reduced to algebraic ones. In the article we present bisingular solution and its topological modifications. Related EM-fields appear to be just the well-known Born solution and its modifications with singular structure of ring-like and toroidal topology. General problems of the algebrodynamical approach are discussed. 
V. V. Kassandrov, J. A. Rizcalla (RPFU, Moscow, Russia)