Vincent van Gogh, Vincent Willem Gogh (1927). “The Letters of Vincent Van Gogh to His Brother, 1872-1886: With a Memoir by His Sister-in-law, J. Van Gogh-Bonger ...”
Viktor Schauberger, Callum Coats (1999). “The Water Wizard – The Extraordinary Properties of Natural Water: Volume 1 of Renowned Environmentalist Viktor Schauberger’s Eco-Technology Series”, p.22, Gill & Macmillan Ltd