1. Agard, S., A geometric proof of Mostow’s rigidity theorem for groups of divergence type ,Acta Math. 151 (1983), 231–252.
2. Ahlfors, L. V., Fundamental polyhedrons and limit point sets of Kleinian groups ,Proc. Nat. Acad. Sci. 55 (1966), 251–254.
3. Ahlfors, L. V., Mobius transformations in several dimensions ,Lecture Notes, School of Mathematics, University of Minnesota (1981).
4. Akaza, T., Poincaré theta series and singualr sets of Schottky groups ,Nagoya Math. J. 24 (1964), 43–65.
5. Akaza, T., Singular sets of some Kleinian groups ,Nagoya Math. J,.