“I continue to find my greatest pleasure, and so my reward, in the work that precedes what the world calls success.” — Thomas Edison, American inventor A. R. Calhoun How to Get On in the World; or, a Ladder to Pratical Success, New York, 1895, p.137.  Digitally archived at: https://www.gutenberg.org/cache/epub/20608/pg20608.html, accessed 18 September 2021.