Boucheron, Stéphane (2013). Concentration Inequalities: a Nonasymptotic Theory of Independence. Gábor Lugosi, Pascal Massart. Oxford: Oxford University Press. p. 21. ISBN978-0-19-953525-5. OCLC837517674.
Vershynin, Roman (2018). High-dimensional probability : an introduction with applications in data science. Cambridge, United Kingdom. p. 19. ISBN978-1-108-41519-4. OCLC1029247498.{{cite book}}: CS1 maint: location missing publisher (link)