“…Recall from [4], Remark 1.1 (3) that if R ⊂ S is an extension of integral domains and if R is a VD in S, then qf(R) = qf(S). Clearly, this may not be true if R is not a VD in S. However, if R is a maximal non VD in S, where R is not a field, then qf(R) = qf(S) as we have the next proposition which is a generalization of [7], Lemma 1 (ii).…”