Singer, Ivan. Abstract convex analysis. New York: John Wiley & Sons, Inc., 1997, p. xxii+491 (Canadian Mathematical Society series of monographs and advanced texts). ISBN 0-471-16015-6.
Takayama, Akira. Analytical Methods in Economics. University of Michigan Press, 1994, p. 54. ISBN 9780472081356. «An often seen confusion is a "concave set". Concave and convex functions designate certain classes of functions, not of sets, whereas a convex set designates a certain class of sets, and not a class of functions. A "concave set" confuses sets with functions.»
Sergio Amat, Francesc Aràndiga, José Vicente Arnau, Rosa M. Donat Beneito, Pep Mulet Mestre, Rosa Peris Sancho. Aproximació numèrica. Universitat de València, 2002, p. 21. ISBN 843705513X.
