Encyclopedia of Triangle Centres Clark Kimberling's definitive site.This now has almost 2500 centres.
With full details of the centres and useful background information.

Edward Brisse's Lists Invaluable lists of centres, and objects, such as lines and
conics containing triangle centres.

Quim Castellsaguer's Site Much useful information, with definitions anf theorems.
Also has Cabri macros to plot centres and illustrate results.

Darij Grinberg's Site Links to some of the author's many contributions to the
subject of triangle centres.

Paul Yiu's Triangle Centres A link to a postscript file (of 147 pages) giving a very good
introduction to triangle centres and associated geometry.

Paul Yiu's Barycentric Coordinates A brief but excellent introduction to barycentric coordinates.

Hyacinthos Newsgroup A Yahoo-group devoted to the geometry of the triangle, with
special emphasis on tringle centres.
Note. My experience is that many mail agents "lose" some Yahoo
messages. An effective remedy is to obtain a (free) Yahoo account.

MathWorld This general mathematical site has many references to triangle
geometry and triangle centres.

main triangle centres page