Wang, Mao Fa et Liu, Pei De, Compactness of Product Operators on the Bergman Space, Acta mathematica Sinica. English series (Print) , 21(4), 2005, pp. 723-732
In this paper, we study the compactness of the product of a composition operator with another ones adjoint on the Bergman space. Some necessary and sufficient conditions for such operators to be compact are given.