1. E.A Velichko and A.P. Nikolaenko, Radiofiz. Radioastron., 18, No. 1, 65 (2013).
2. E.A Velichko and A.P. Nikolaenko, Radiofiz. Élektron., 14, No. 1, 11 (2009).
3. E.A Velichko and A.P. Nikolaenko, Radiofiz. Élektron., 1 (15), No. 3, 17 (2010).
4. E. Jahnke, F. Emde, and F. Losch, Tables of Higher Functions, McGraw Hill, New York (1960).
5. V. G.Veselago, Sov. Phys., 10, 509 (1968).