Finno-Soviet Treaty of 1948
The Agreement of Friendship, Cooperation, and Mutual Assistance of 1948, also known as the YYA Treaty from the Finnish Ystävyys-, yhteistyö- ja avunantosopimus (YYA-sopimus) (Swedish: Vänskaps-, samarbets- och biståndsavtalet (VSB-avtalet)), was the basis for Finno–Soviet relations from 1948 to 1992. It was the main instrument in implementing the Finnish policy called Paasikivi–Kekkonen doctrine.
Source: Wikipedia — Finno-Soviet Treaty of 1948 (CC BY-SA 4.0)