1. J. E. Littlewood, ?On some conjectural inequalities with applications to the theory of integral functions,? J. London Math. Soc.,97, No. 4, 387?392 (1952).
2. W. K. Hayman, ?On a conjecture of Littlewood,? J. Anal. Math.,36, 75?95 (1979).
3. A. É. Eremenko and M. M. Sodin, ?Proof of a conditional theorem of Littlewood on the distribution of values of entire functions,? Izv. Akad. Nauk SSSR, Ser. Mat.,51, No. 2, 421?428 (1987).
4. D. Gaier, Lectures on the Theory of Approximation in the Complex Domain [Russian translation], Mir, Moscow (1986).