found: The prince of Scandinavia, 2015:t.p. (Prince Christian August)
found: OCLC #12623171: The prince of Scandinavia : a biography of Prince Christian August of Schleswig-Holstein-Sonderburg-Augustenburg, 1768-1810, 1975.
found: LC database, Dec. 16, 2016(heading: Karl August, Crown Prince of Sweden, 1768-1810; usage: Karl August)
found: Swedish Wikipedia, viewed Dec. 16, 2016(Karl August; originally Fredrik Kristian August av Augustenburg; b. July 9, 1768, Augustenborgs slott, Denmark; d. May 28, 1810, Kvidinge hed, Skåne; third son of Duke Kristian Fredrik av Slesvig-Holstein-Sönderborg-Augustenborg; briefly Crown Prince of Sweden)
found: Danish Wikipedia, viewed Dec. 16, 2016(under Christian August af Slesvig-Holsten-Sønderborg-Augustenborg: Christian August, prins af Slesvig-Holsten-Sønderborg-Augustenborg, later Karl August, kronprins af Sverige)
found: Wikipedia, viewed Dec. 16, 2016(under Charles August, Crown Prince of Sweden: Charles August or Carl August; b. July 9, 1768, Augustenborg Palace, Augustenborg, Denmark; d. May 28, 1810, Kvidinge, Sweden; Danish prince; best known for serving as Crown Prince of Sweden briefly in 1810, adopted by Charles XIII, before his sudden death from stroke; earlier he had been a general in the Royal Danish Army as well as the Danish governor-general of Norway; his name before assuming the Swedish title in 1810 was Christian August of Schleswig-Holstein-Sonderburg-Augustenborg, Christian August of Augustenborg for short; as Crown Prince of Sweden, he changed his name to Charles August (Swedish: Carl August))
found: Britannica academic WWW site, viewed Dec. 16, 2016(under Charles XIII: the Riksdag provided for the succession by naming Duke Christian August (later Charles August) heir apparent; d. 1810)