Quotient divisible groups of rank 2

In the paper, representations of torsion-free Abelian groups of rank 2 using torsion-free groups of rank 1 are studied. Necessary and sufficient conditions are found under which a group given by such a representation is quotient divisible. A criterion is obtained for two p-minimal quotient divisible torsion-free groups of rank 2 to be isomorphic to each other. An example is constructed showing that two such groups can be embedded in each other but be nonisomorphic. A series of properties of fundamental systems of elements of quotient divisible groups of arbitrary finite rank is established