On balanced Cayley maps over abelian groups

A notion of a balanced automorphism of a group was introduced in [J. Sirǎn and M. Skoviera. Regular maps from Cayley graphs. I. Balanced Cayley maps. Algebraic graph theory (Leibnitz, 1989). Discrete Math. 109 (1992), no. 1–3, 265–276] in order to study regular Cayley maps over finite groups. One of the open questions formulated in the paper was this: which finite abelian groups admit a balanced automorphism? The presented paper answers this question.