“…This issue was reviewed several times (Poljakov, 1881;Vinogradov, 1933;Ognev, 1950;Vinogradov & Gromov, 1952;Gromov et al, 1963;Kuziakin, 1963;Gromov & Polyakov, 1977;Zagorodnyuk, 1990;Pozdniakov, 1993;Meyer et al, 1996;Litvinov, 2001;Kartavtseva et al, 2008;Frisman et al, 2009;Sheremetyeva et al, 2009;Bannikova et al, 2010;Haring et al, 2011;Abramson & Lissovsky, 2012).…”