Claudi Alsina, Roger B. Nelsen: Icons of Mathematics. An Exploration of Twenty Key Images. Springer, 2011, ISBN 99780883859865, pp. 112–113 (excerpt (Google), p. 112, at Google Books)
cut-the-knot.org
Taylor-Kreis at cut-the-knot.org (retrieved 2024-0-2-9)
