The case of the marriage of her Imperial Highness Grand Duchess Maria Aleksandrovna

V.F.Piotrovsky and B.P.Von Ditmar.To the limnology of the Petrozavodsk district, the Olonets province.(A preliminary report on the work performed on the lakes: Ukshozer, Konchozer, Uzchozer, Port-Novotsky, Padozer and Gabozere).- 1911. -Agreement No. 24 of 02/12/2016 category 25 manuscript of the works of members of the Russian Geographical Society and separate documents in the Olonets province, case 65..Electronic copy source: PB