1. Archival sources
2. Riksregistraturet [Royal correspondence register of the realm], Swedish National Archives, SVAR, digital research room.
3. Originaltraktater med främmande makter (traktater), Ryssland [Original treaties with foreign powers, Russia], SE/RA(25.3./2/1 (1561). Swedish National Archives. SVAR, digital research room.
4. Originaltraktater med främmande makter (traktater) [Original treaties with foreign powers], 10 augusti 1583 (7091), SE/RA/25.3/2/3/C (1582-1583). Swedish National Archives. SVAR, digital research room.
5. Internet sources