  Singular overpartitions, which are defined by George Andrews, are
overpartitions whose Frobenius symbols have at most one overlined entry in each
row. In his paper, Andrews obtained interesting combinatorial results on
singular overpartitions, one of which relates a certain type of singular
overpartitions with a subclass of overpartitions. In this paper, we provide a
combinatorial proof of Andrews' result, which answers to one of his open
questions.
