Nikolai Constant.Sergeev.Russian folk songs.Author - act.A student of Moscow University, an employee in the Kursk Civil Chamber.

Nikolai Constant.Sergeev.Russian folk songs.Author - act.A student of Moscow University, an employee in the Kursk Civil Chamber.- -.-Agreement No. 24 of 02/12/2016 category 29 of the manuscript of the works of members of the Russian Geographical Society and separate documents in the Kursk province, case 9..Electronic copy source: PB