1. B. Ya. Levin, Distribution of Zeros of Entire Functions (Gostekhizdat, Moscow, 1956) [in Russian].
2. A.F. Leont’ev, Entire Functions. Series of Exponentials (Nauka, Moscow, 1983) [in Russian].
3. A. F. Leont’ev, Exponential Series (Nauka, Moscow, 1976) [in Russian].
4. A. S. Krivosheev, “The fundamental principle for invariant subspaces in convex domains,” Izv. Ross. Akad. Nauk, Ser. Mat. 68 (2), 71–136 (2004).
5. O. A. Krivosheyeva, “Singular points of the sum of a series of exponential monomials on the boundary of the convergence domain,” SPb. Math. J. 23, 321–350 (2012).