1. Basicity of an exponential system and Muckenhoupt's condition;Pavlov;Soviet Math. Dokl.,1979
2. 6. Yu. I. Lyubarskii, Private Communication, 1993.
3. On the question of Riesz bases of complex exponential functions in L2;Avdonin;Vestnik Leningrad Univ. Ser. Mat.,1974