Morphisms of Ball's Structures of Groups and Graphs
We introduce and study two kinds of morphisms between ball's structures related to groups and graphs.
English version (Springer): Ukrainian Mathematical Journal 54 (2002), no. 6, pp 1027-1037.
Citation Example: Protasov I. V. Morphisms of Ball's Structures of Groups and Graphs // Ukr. Mat. Zh. - 2002. - 54, № 6. - pp. 847-855.