↑ Taylor, Alan. American Colonies. Penguin: London (2001).
↑ For example: Feig, Konnilyn G. (1981). Hitler's Death Camps: The Sanity of Madness . Holmes & Meier Publishers. tr. 296. ISBN9780841906761. Truy cập ngày 29 tháng 6 năm 2015. [...] a forced-labor camp [...] named Arbeitslager Treblinka I [...] an order exists, dated 15 November 1941, establishing that penal colony.
↑ Jager, Sheila Miyoshi (2013). Brothers at War: The Unending Conflict in Korea. Profile Books. tr. 458. ISBN9781847652027. Truy cập ngày 29 tháng 6 năm 2015. Prison labor camps, or kwalliso, were first established in North Korea after liberation from Japan to imprison enemies of the revolution, landowners, collaborators, and religious leaders. After the war, these places housed un-repatriated South Korean prisoners of war. [...] There are six such camps in existence today, according to a May 2011 Amnesty International report, 'huge areas of land and located in vast wilderness sites in South Pyong'an, South Hamyong and North Hamyong Provinces.' ... Perhaps the most notorious penal colony is kwalliso no. 15. or Yodok [...].
↑ Stewart, John (2006). African States and Rulers (ấn bản 3). McFarland & Company. tr. 96. ISBN9780786425624. Truy cập ngày 29 tháng 6 năm 2015. From 1879 the Spanish basically used Fernando Po as a penal colony for captured Cuban rebels.
↑ Gates, David (1986). The Spanish Ulcer: A History of the Peninsular War. W W Norton & Co. ISBN0-393-02281-1.
