Laursen, L. (1917). "1640. 22. April (Flensborg). Handels- og Toldtrakat paa 6 Aar mellem Danmark-Norge og Storbritannien; med dertil horende Toldrulle.- Ikke ratificeret fra engelsk Side." [1640. April 22 (Flensburg). Trade and Customs Treaty of 6 years between Denmark-Norway and Great Britain; with associated Customs Roll.- Not ratified by English Side.]. Traites du Danemark et de la Norvege. Danmark-Norges Traktater 1523—1750 Med dertil horende aktstykker: Tredie Bind (1589-1625) [[Treaties of Denmark-Norway (1523-1750) with Associated Acts- Volume 3 (1589-1625)]] (in Danish). Vol. 3. Copenhagen: L. Laursen, Carlsberg Foundation. p. 210. Retrieved 26 May 2022 – via Rigsarkivet.