円に内接する四角形
↑ Peter, Thomas (September 2003), “Maximizing the area of a quadrilateral”, The College Mathematics Journal 34 (4): 315–6, doi:10.2307/3595770, JSTOR 3595770, https://jstor.org/stable/3595770
1 2 Coxeter & Greitzer 1967.
↑ Prasolov, Viktor, Problems in plane and solid geometry: v.1 Plane Geometry, http://students.imsa.edu/~tliu/Math/planegeo.pdf
↑ Alsina & Nelsen 2009.
1 2 3 Alsina & Nelsen 2007.
1 2 Johnson 2007.
1 2 Inequalities proposed in "Crux Mathematicorum", 2007, .
↑ “ABCD is a cyclic quadrilateral. Let M, N be midpoints of diagonals AC, BD respectively...”, Art of Problem Solving, (2010), http://www.artofproblemsolving.com/Forum/viewtopic.php?f=46&t=350179
↑ A.