1. British Library, Add MS 15856, f. 17: Charles I to the Grand Signor Ibrahim: 24 November, 1646.
2. Rigsarkivet (Danish National Archives), Tyske Kancellis udenrigske afdeling (German Chancellery, Foreign Division), England: Breve, til dels med bilag, fra Oliver og Richard Cromwell og fra Parlamentet til kong Frederik III (England: Letters, partly with annexes, from Oliver and Richard Cromwell and from Parliament to King Frederik III), No. 176, 177, 178: 24 October 1648, Letter from Charles I to Frederick III.
3. Russkii Gosudarstvennyi arkhiv drevnikh aktov (Russian State Archive of Ancient Acts/RGADA, Posol’skii Prikaz, (Ambassadorial or Foreign Office), Fond 35: Snosheniia Rossii s Angliei (Anglo-Russian Relations)
4. • Opis’ 1 (Documents on political, commercial, and cultural relations between Russia and England), Nos. 154, 157 163, 164, 165, 168, 169, 177.
5. • Opis’ 2 (Letters from the English monarchs to the Russian tsars), No. 76: 1 June 1642, Charles I to Mikhail; No. 77: 6 June 1642, Charles I to Mikhail; No. 78: Not dated, Parliament to Aleksei; No. 79: 7 December 1646, Charles I to Aleksei; No. 80: 31 March 1647, Charles I to Aleksei; No. 81: 1 June 1648, Charles I to Aleksei; No. 82: 16 December 1648, Charles, Prince of Wales to Aleksei; No. 83: 16 September 1649, Charles II to Aleksei.