January 1962
"During the period covered by this report, the Vopo [GDR People's Police] set up winter-proof barracks for inspection or accommodation purposes at the sector border crossings Heinrich-Heine Strasse, Sonnenallee, Chausseestrasse and Bornholmer Strasse. This work was concluded on 31.1.1962. The reinforcement of the eastern border barriers along the remaining parts of the sector and zone border was continued," the West Berlin police write in their monthly report on developments on the sector and zone border in January.
Progress report by the West Berlin police for the month of January 1962 (in German)