^{(Joost Evers / Anefo - Creative Commons Zero, Public Domain Dedication)}

^{(World Economic Forum - Creative Commons Attribution 3.0)}

^{(NASA, ESA, CSA, STScI - Public domain)}

^{(Jesse Krauß - Public domain)}

^{(www.elbpresse.de -  Creative Commons Attribution-Share Alike 4.0 International)}

^{(Marshal Giancarlo Cecconi - public domain)}