Chetyrekhstoronnee soglashenie po Zapadnomu Berlinu i ego realizat︠s︡ii︠a︡, 1971-1977 gg. : dokumenty /
Erickson, John,1929-2002,former owner.StEdNL
Erickson, Ljubica,former owner.StEdNL
Soviet Union.Ministerstvo inostrannykh del.
Germany (East).Ministerium für Auswärtige Angelegenheiten.
Moskva : Politizdat,
1977.
At head of title: Ministerstvo inostrannykh del SSSR. Ministerstvo inostrannykh del GDR.
John and Ljubica Erickson collection.
Quadripartite Agreement on Berlin (1971)