WRITER, Rebekah Valentine Senior Staff. Hearts of Iron IV sells one million copies [online]. GamesIndustry.biz, 2018-05-21, [cit. 2023-05-23]. Dostupné online. (po anglicky)
gamewatcher.com
Hearts of Iron IV developer diary talks about nuclear | GameWatcher [online]. www.gamewatcher.com, [cit. 2023-05-23]. Dostupné online. (po anglicky)
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Apolon. 'Hearts Of Iron 4' Beginner's Guide: Tips, Tricks and Strategies For Mastering The Basics. Player.One, June 29, 2016. Dostupné online [cit. 2019-01-08]. Archivované 2019-02-21 na Wayback Machine
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Paradox sells over 500,000 copies of WWII grand strategy game Hearts of Iron IV [online]. 2017-02-20, [cit. 2023-05-23]. Dostupné online. (po anglicky)
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Apolon. 'Hearts Of Iron 4' Beginner's Guide: Tips, Tricks and Strategies For Mastering The Basics. Player.One, June 29, 2016. Dostupné online [cit. 2019-01-08]. Archivované 2019-02-21 na Wayback Machine