Sorry that I cannot give you more information, as the following:
The city "Gadesnstedt" should most probably read as "Gadenstedt". It is a part now of the community of "Lahstedt" in the County of Peine, close to Hanover, the capital of Lower Saxony.
As your great grandmother Fredericka was born in 1915, the town hall should have a copy of their death certificate. I only do not know whether they would speak English.
The death certificate might also tell you about her marriage to Wilhelm Burgdorf.
Address:
Gemeinde Lahstedt,
Standesamt,
Ms. Harms,
Am Breiten Tor 1,
31246 Lahstedt/Gadenstedt
Germany
Phone +49 (5172) 9890-21, Fax +49 (5172) 9890-42
eMail:
info@Lahstedt.deRegards, Jens Oelgardt, eMail:
JOelgardt@aol.com