1. Baevskiy R.M., Ivanov G.G., Ryabykina G.V. Arrhythmolo-gy gazette, 1999, no. 14, pp. 71–75 (in Russian).
2. Kulakov V.I., Savel'eva G.M., Strizhakov A.N. Obstetrics. Moscow, Medicine Publ., 2006. 816 p (in Russian).
3. Tsoy E.G., Igisheva L.N., Galeeva A.R. Pediatrics, 2003, no. 1, pp. 23–24 (in Russian).