Editing Nine-point circle (section)

== References ==

* {{ citation | first1 = Nathan | last1 = Altshiller-Court | year = 1925 | lccn = 52013504 | title = College Geometry: An Introduction to the Modern Geometry of the Triangle and the Circle | edition = 2nd | publisher = [[Barnes & Noble]] | location = New York }}
* {{citation | last1 = Feuerbach | first1 = Karl Wilhelm | author1-link = Karl Wilhelm Feuerbach | last2 = Buzengeiger | first2 = Carl Heribert Ignatz | author2-link = Carl Heribert Ignatz Buzengeiger | year = 1822 | title = Eigenschaften einiger merkwürdigen Punkte des geradlinigen Dreiecks und mehrerer durch sie bestimmten Linien und Figuren. Eine analytisch-trigonometrische Abhandlung | publisher = Wiessner | location = Nürnberg | edition = Monograph | url = http://resolver.sub.uni-goettingen.de/purl?PPN512512426 }}.
* {{ citation | first1 = David C. | last1 = Kay | year = 1969 | lccn = 69012075 | title = College Geometry | publisher = [[Holt, Rinehart and Winston]] | location = New York }}
* {{ citation | first1 = David | last1 = Fraivert 
 | journal = [[The Mathematical Gazette]]
 | pages = 222–232
 | title = New points that belong to the nine-point circle
 | volume = 103
 | issue = 557
 | year = 2019| doi = 10.1017/mag.2019.53 | s2cid = 213935239 
 }}
* {{ citation | first1 = David | last1 = Fraivert 
 | journal = [[International Journal of Geometry]]
 | pages = 5–16
 | title = New applications of method of complex numbers in the geometry of cyclic quadrilaterals
 | url = https://ijgeometry.com/wp-content/uploads/2018/04/5-16.pdf
 | volume = 7
 | issue = 1
 | year = 2018}}