M.F.Sysoeva.Songs collected in the Gdovsky district, Petrograd province.Manuscript material.

M.F.Sysoeva.Songs collected in the Gdovsky district, Petrograd province.Manuscript material.- 1920. -Agreement No. 24 of 02/12/2016 category 35 manuscript of the works of members of the Russian Geographical Society and separate documents in the Petrograd province, case 27..Electronic copy source: PB