An {\em MV-pair} is a pair (B,G) where B is a Boolean algebra and G is
a subgroup of the automorphism group of B satisfying certain conditions. Let
∼G be the equivalence relation on B naturally associated with G. We
prove that for every MV-pair (B,G), the effect algebra B/∼G is an MV-
effect algebra. Moreover, for every MV-effect algebra M there is an MV-pair
(B,G) such that M is isomorphic to B/∼G