Modern Geometry of the Triangle: https://t.co/asTXe1va9T
A Tour of Triangle Geometry: https://t.co/UBTM1Mztu6
Coxeter's Kaleidoscopes: https://t.co/cwRzd6ZRjy
The Complete Quadrilateral: https://t.co/9Rcu1gSbYm

— Steve Phelps (@MathTechCoach) June 6, 2019