
[Martinus Veltman, Facts and mysteries in elementary particle physics, World Scientific, 2003, 981238149X, 308, https://books.google.com/books?id=CNCHDIobj0IC&pg=PA308]
Foreward, written June 30, 1999, to Supersymmetry: Unveiling the Ultimate Laws of Nature (2000) by Gordon Kane
[Martinus Veltman, Facts and mysteries in elementary particle physics, World Scientific, 2003, 981238149X, 308, https://books.google.com/books?id=CNCHDIobj0IC&pg=PA308]
“Supersymmetry arises naturally in string theory.”
It was originally motivated by string theory.
Source: [The World's Largest Experiment, 2013, https://www.sns.ias.edu/sites/default/files/World's_largest_experiment_%20Delhi.pdf] (public talk at Tryst, Indian Institute of Technology Delhi)
“The only string theories we really understand well have exact supersymmetry.”
Source: [Loose Ends: String Theory and the Quest for the Ultimate Theory, World Science Festival, 2 August 2019, https://www.youtube.com/watch?v=YSWd21z2qqE] (quote at 40:20 of 1:27:24)
[Schwarz, J. H., Introduction to superstring theory, 2000, arXiv preprint arXiv:hep-ex/0008017, http://arxiv.org/abs/hep-ex/0008017] p. 5
"David J. Gross - Biographical" http://www.nobelprize.org/nobel_prizes/physics/laureates/2004/gross-bio.html, Nobel Prize in Physics, nobelprize.org (2004)
Source: Warped Passages: Unraveling the Universe's Hidden Dimensions (2005), Ch. 24.
[Physics Today, A Lowbrow's View of Feynman, 42, 2, 1989, 10.1063/1.881197] (p. 85)